diff --git a/Changes b/Changes
index e327a80..0fc0bb3 100644
--- a/Changes
+++ b/Changes
@@ -1,7 +1,7 @@
 0.49.3 2014-01-29
         - [documentation] Improved documentation for API classes (diewald)
 	- [documentation] Improved documentation for various queries (margaretha)
-	- [feature] Added deserialization of SpanSubSpanQueries (margaretha)
+	- [feature] Added deserialization of SpanSubSpanQueries (margaretha,diewald)
 	- [bugfix] Null filters are now correctly extended (diewald)
 	- [cleanup] Refactoring of KorapResult, KorapResponse, KorapQuery,
 	  deprecated operation:or in favor of operation:junction (diewald)
diff --git a/src/main/java/de/ids_mannheim/korap/KorapQuery.java b/src/main/java/de/ids_mannheim/korap/KorapQuery.java
index b7c3fcc..9ad167c 100644
--- a/src/main/java/de/ids_mannheim/korap/KorapQuery.java
+++ b/src/main/java/de/ids_mannheim/korap/KorapQuery.java
@@ -233,7 +233,6 @@
 
                 number = json.get("classRef").get(0).asInt();
 
-
                 if (number > MAX_CLASS_NUM)
                     throw new QueryException(
                         709,
@@ -244,7 +243,8 @@
             // Reference based on spans
             else if (json.has("spanRef")) {
                 JsonNode spanRef = json.get("spanRef");
-                int length=0;
+                int length = 0;
+                int startOffset = 0;
                 if (!spanRef.isArray() || spanRef.size() == 0) {
                     throw new QueryException(
                         714,
@@ -252,14 +252,17 @@
                         " and a length parameter"
                     );
                 };
-	        	        
-                if (!spanRef.get(1).isMissingNode())
-                    length = spanRef.get(1).asInt();
+                
+                if (spanRef.size() > 1)
+                    length = spanRef.get(1).asInt(0);
 	            
+                startOffset = spanRef.get(0).asInt(0);
+
+                if (DEBUG) log.trace("Wrap span reference {},{}", startOffset, length);
+
                 return new SpanSubspanQueryWrapper(
-                    fromJson(operands.get(0)), spanRef.get(0).asInt(),
-                    length
-                ); 
+                    this.fromJson(operands.get(0)), startOffset, length
+                );
             };
 
             if (DEBUG) log.trace("Wrap class reference {}", number);
@@ -273,6 +276,7 @@
             if (!json.has("wrap"))
                 return new SpanRepetitionQueryWrapper();
 
+            // Get wrapped token
             return this._segFromJson(json.get("wrap"));
 
         case "korap:span":
@@ -283,6 +287,7 @@
         throw new QueryException(713, "Query type is not supported");
     };
 
+
     // Deserialize korap:group
     private SpanQueryWrapper _groupFromJson (JsonNode json) throws QueryException {
 
@@ -348,6 +353,7 @@
         return ssaq;
     };
 
+
     // Deserialize operation:position
     private SpanQueryWrapper _operationPositionFromJson (JsonNode json, JsonNode operands)
         throws QueryException {
@@ -438,6 +444,7 @@
         );
     };
 
+
     // Deserialize operation:repetition
     private SpanQueryWrapper _operationRepetitionFromJson (JsonNode json, JsonNode operands)
         throws QueryException {
@@ -445,8 +452,7 @@
         if (operands.size() != 1)
             throw new QueryException(705, "Number of operands is not acceptable");
 
-        int min = 0;
-        int max = 100;
+        int min = 0, max = 100;
 
         if (json.has("boundary")) {
             Boundary b = new Boundary(json.get("boundary"), 0, 100);
@@ -504,6 +510,7 @@
         if (operands.size() != 1)
             throw new QueryException(705, "Number of operands is not acceptable");
 
+        // Use class reference
         if (json.has("classRef")) {
             if (json.has("classRefOp")) {
                 throw new QueryException(
@@ -514,6 +521,8 @@
 
             number = json.get("classRef").get(0).asInt();
         }
+
+        // Use span reference
         else if (json.has("spanRef")) {
             throw new QueryException(
                 762,
@@ -599,6 +608,7 @@
     // Deserialize operation:sequence
     private SpanQueryWrapper _operationSequenceFromJson (JsonNode json, JsonNode operands)
         throws QueryException {
+
         // Sequence with only one operand
         if (operands.size() == 1)
             return this.fromJson(operands.get(0));
@@ -710,14 +720,14 @@
 
         // inOrder was set to false without a distance constraint
         if (!sseqqw.isInOrder() && !sseqqw.hasConstraints()) {
-            sseqqw.withConstraint(1,1,"w");
+            sseqqw.withConstraint(1, 1, "w");
         };
 
         return sseqqw;
     };
 
 
-    // Segment
+    // Deserialize korap:token
     private SpanQueryWrapper _segFromJson (JsonNode json) throws QueryException {
         if (!json.has("@type"))
             throw new QueryException(701, "JSON-LD group has no @type attribute");
@@ -727,6 +737,7 @@
         if (DEBUG)
             log.trace("Wrap new token definition by {}", type);
 
+        // Branch on type
         switch (type) {
         case "korap:term":
             String match = "match:eq";
@@ -734,13 +745,18 @@
                 match = json.get("match").asText();
             
             switch (match) {
+
             case "match:ne":
                 if (DEBUG)
                     log.trace("Term is negated");
+
                 SpanSegmentQueryWrapper ssqw =
                     (SpanSegmentQueryWrapper) this._termFromJson(json);
+
                 ssqw.makeNegative();
+
                 return this.seg().without(ssqw);
+
             case "match:eq":
                 return this._termFromJson(json);
             };
@@ -796,13 +812,23 @@
     };
 
 
-    private SpanQueryWrapper _termFromJson (JsonNode json) throws QueryException {
+    // Deserialize korap:term
+    private SpanQueryWrapper _termFromJson (JsonNode json)
+        throws QueryException {
 
-        if (!json.has("key") || json.get("key").asText().length() < 1)
-            throw new QueryException(740, "Key definition is missing in term or span");
+        if (!json.has("key") || json.get("key").asText().length() < 1) {
+            throw new QueryException(
+                740,
+                "Key definition is missing in term or span"
+            );
+        };
 	    
-        if (!json.has("@type"))
-            throw new QueryException(701, "JSON-LD group has no @type attribute");
+        if (!json.has("@type")) {
+            throw new QueryException(
+                701,
+                "JSON-LD group has no @type attribute"
+            );
+        };
 
         Boolean isTerm = json.get("@type").asText().equals("korap:term") ? true : false;
         Boolean isCaseInsensitive = false;
@@ -845,15 +871,16 @@
                 layer = "c";
                 break;
 
-                case "cat":
-                    layer = "c";
-                    break;
+                /*
+                  case "cat":
+                  layer = "c";
+                  break;
+                */
             };
 
             if (isCaseInsensitive && isTerm) {
-                if (layer.equals("s")) {
+                if (layer.equals("s"))
                     layer = "i";
-                }
                 else {
                     this.addWarning(
                         767,
@@ -879,13 +906,18 @@
 
         // Regular expression or wildcard
         if (isTerm && json.has("type")) {
+
+            // Branch on type
             switch (json.get("type").asText()) {
             case "type:regex":
                 return this.seg(this.re(value.toString(), isCaseInsensitive));
+
             case "type:wildcard":
                 return this.seq(this.wc(value.toString(), isCaseInsensitive));
+
             case "type:string":
                 break;
+
             default:
                 this.addWarning(746, "Term type is not supported - treated as a string");
             };
@@ -895,40 +927,48 @@
             return this.seg(value.toString());
 
         if (json.has("attr")) {
-
             this.addWarning(
-                    768,
-                    "Attributes are currently not supported - results may not be correct");
+                768,
+                "Attributes are currently not supported - results may not be correct"
+            );
 
             // SpanQueryWrapper attrQueryWrapper =
-            // handleAttr(json.get("attr"));
+            // _attrFromJson(json.get("attr"));
             // if (attrQueryWrapper != null) {
             // return seg SpanElementWithAttributeQueryWrapper
             // }
-        }
+        };
+
         return this.tag(value.toString());
     };
 
-    private SpanQueryWrapper handleAttr(JsonNode attrNode)
-            throws QueryException {
+
+    private SpanQueryWrapper _attrFromJson (JsonNode attrNode)
+        throws QueryException {
 
         if (!attrNode.has("@type")) {
-            throw new QueryException(701,
-                    "JSON-LD group has no @type attribute");
-        }
+            throw new QueryException(
+                701,
+                "JSON-LD group has no @type attribute"
+            );
+        };
 
         if (attrNode.get("@type").asText().equals("korap:term")) {
             if (attrNode.has("tokenarity") || attrNode.has("arity")) {
                 this.addWarning(
-                        768,
-                        "This kind of attributes are currently not supported - results may not be correct");
-            }
+                    770,
+                    "Arity attributes are currently not supported" +
+                    " - results may not be correct"
+                );
+            };
+
             if (attrNode.has("root")) {
                 String rootValue = attrNode.get("root").asText();
                 if (rootValue.equals("true") || rootValue.equals("false")) {
                     return new SpanAttributeQueryWrapper(
-                            new SpanSimpleQueryWrapper("tokens", "@root"),
-                            Boolean.valueOf(rootValue));
+                        new SpanSimpleQueryWrapper("tokens", "@root"),
+                        Boolean.valueOf(rootValue)
+                    );
                 }
                 // wrong root value
             }
@@ -941,6 +981,7 @@
         return null;
     }
 
+
     /**
      * Create a query object based on a regular expression.
      *
diff --git a/src/main/java/de/ids_mannheim/korap/query/wrap/SpanClassQueryWrapper.java b/src/main/java/de/ids_mannheim/korap/query/wrap/SpanClassQueryWrapper.java
index c455396..d276cb1 100644
--- a/src/main/java/de/ids_mannheim/korap/query/wrap/SpanClassQueryWrapper.java
+++ b/src/main/java/de/ids_mannheim/korap/query/wrap/SpanClassQueryWrapper.java
@@ -34,16 +34,20 @@
     };
 
     public SpanQuery toQuery () throws QueryException {
-	if (this.subquery.isNull())
-	    return (SpanQuery) null;
+        if (this.subquery.isNull())
+            return (SpanQuery) null;
 
-	// TODO: If this.subquery.isNegative(), it may be an Expansion!
-	// SpanExpansionQuery(x, y.negative, min, max. direction???, classNumber, true)
+        SpanQuery sq = (SpanQuery) this.subquery.toQuery();
+
+        if (sq == null) return (SpanQuery) null;
+
+        // TODO: If this.subquery.isNegative(), it may be an Expansion!
+        // SpanExpansionQuery(x, y.negative, min, max. direction???, classNumber, true)
 	
-	if (this.number == (byte) 0) {
-	    return new SpanClassQuery((SpanQuery) this.subquery.toQuery());
-	};
-	return new SpanClassQuery((SpanQuery) this.subquery.toQuery(), (byte) this.number);
+        if (this.number == (byte) 0) {
+            return new SpanClassQuery(sq);
+        };
+        return new SpanClassQuery(sq, (byte) this.number);
     };
 
     public boolean isOptional () {
diff --git a/src/main/java/de/ids_mannheim/korap/query/wrap/SpanSequenceQueryWrapper.java b/src/main/java/de/ids_mannheim/korap/query/wrap/SpanSequenceQueryWrapper.java
index 4ed1223..9df3c6d 100644
--- a/src/main/java/de/ids_mannheim/korap/query/wrap/SpanSequenceQueryWrapper.java
+++ b/src/main/java/de/ids_mannheim/korap/query/wrap/SpanSequenceQueryWrapper.java
@@ -31,11 +31,12 @@
     private ArrayList<DistanceConstraint> constraints;
 
     private final String limitationError =
-	"Distance constraints not supported with " +
-	"empty or negative operands";
+        "Distance constraints not supported with " +
+        "empty or negative operands";
 
     // Logger
-    private final static Logger log = LoggerFactory.getLogger(SpanSequenceQueryWrapper.class);
+    private final static Logger log =
+        LoggerFactory.getLogger(SpanSequenceQueryWrapper.class);
 
     // This advices the java compiler to ignore all loggings
     public static final boolean DEBUG = false;
@@ -45,12 +46,13 @@
     // The sequence is problem solved
     private boolean isSolved = false;
 
+
     /**
      * Empty constructor.
      */
     public SpanSequenceQueryWrapper (String field) {
-	this.field = field;
-	this.segments = new ArrayList<SpanQueryWrapper>(2);
+        this.field = field;
+        this.segments = new ArrayList<SpanQueryWrapper>(2);
     };
 
 
@@ -58,15 +60,15 @@
      * Constructor accepting term sequences.
      */
     public SpanSequenceQueryWrapper (String field, String ... terms) {
-	this(field);
-	for (int i = 0; i < terms.length; i++) {
-	    this.segments.add(
+        this(field);
+        for (int i = 0; i < terms.length; i++) {
+            this.segments.add(
                 new SpanSimpleQueryWrapper(
                     new SpanTermQuery(new Term(field, terms[i]))
                 )
             );
-	};
-	this.isNull = false;
+        };
+        this.isNull = false;
     };
 
 
@@ -74,9 +76,9 @@
      * Constructor accepting SpanQuery sequences.
      */
     public SpanSequenceQueryWrapper (String field, SpanQuery sq) {
-	this(field);
-	this.segments.add(new SpanSimpleQueryWrapper(sq));
-	this.isNull = false;
+        this(field);
+        this.segments.add(new SpanSimpleQueryWrapper(sq));
+        this.isNull = false;
     };
 
 
@@ -85,26 +87,26 @@
      * These wrappers may be optional, negative or empty.
      */
     public SpanSequenceQueryWrapper (String field, SpanQueryWrapper sswq) {
-	this(field);
+        this(field);
 
-	// Ignore null queries
-	if (sswq.isNull())
-	    return;
+        // Ignore null queries
+        if (sswq.isNull())
+            return;
 
-	if (DEBUG && !sswq.isEmpty) {
-	    try {
-		log.trace("New span sequence {}", sswq.toQuery().toString());
-	    }
-	    catch (QueryException qe) {
-		log.trace("Unable to serialize query {}", qe.getMessage());
-	    };
-	};
-	/*
-	System.err.println("Is negative: ");
-	System.err.println(sswq.isNegative());
-	*/
-	this.segments.add(sswq);
-	this.isNull = false;
+        if (DEBUG && !sswq.isEmpty) {
+            try {
+                log.trace("New span sequence {}", sswq.toQuery().toString());
+            }
+            catch (QueryException qe) {
+                log.trace("Unable to serialize query {}", qe.getMessage());
+            };
+        };
+        /*
+          System.err.println("Is negative: ");
+          System.err.println(sswq.isNegative());
+        */
+        this.segments.add(sswq);
+        this.isNull = false;
     };
 
 
@@ -318,125 +320,149 @@
      * Serialize Query to Lucene SpanQueries
      */
     public SpanQuery toQuery () throws QueryException {
+        int size = this.segments.size();
 
-	int size = this.segments.size();
+        // Nothing to do
+        if (size == 0 || this.isNull())
+            return (SpanQuery) null;
 
-	// Nothing to do
-	if (size == 0 || this.isNull())
-	    return (SpanQuery) null;
+        // No real sequence - only one element
+        if (size == 1) {
 
-	// No real sequence - only one element
-	if (size == 1) {
+            // But the element may be expanded
+            if (this.segments.get(0).isExtended() &&
+                (this.hasConstraints() || !this.isInOrder())) {
+                throw new QueryException(613, limitationError);
+            };
 
-	    // But the element may be expanded
-	    if (this.segments.get(0).isExtended() &&
-		(this.hasConstraints() || !this.isInOrder())) {
-		throw new QueryException(613, limitationError);
-	    };
+            // Unproblematic single query
+            if (this.segments.get(0).maybeAnchor())
+                return (SpanQuery) this.segments.get(0).toQuery();
 
-	    // Unproblematic single query
-	    if (this.segments.get(0).maybeAnchor())
-		return (SpanQuery) this.segments.get(0).toQuery();
+            if (this.segments.get(0).isEmpty())
+                throw new QueryException(613, "Sequence is not allowed to be empty");
 
-	    if (this.segments.get(0).isEmpty())
-		throw new QueryException(613, "Sequence is not allowed to be empty");
-	    if (this.segments.get(0).isOptional())
-		throw new QueryException(613, "Sequence is not allowed to be optional");
-	    if (this.segments.get(0).isNegative())
-		throw new QueryException(613, "Sequence is not allowed to be negative");
-	};
+            if (this.segments.get(0).isOptional())
+                throw new QueryException(613, "Sequence is not allowed to be optional");
 
-	if (!this.isSolved) {
-	    if (!_solveProblematicSequence()) {
-		if (this.segments.get(0).maybeExtension())
-		    throw new QueryException(
-			613,
-		        "Sequence contains unresolvable "+
-			"empty, optional, or negative segments"
-		    );
-	    };
-	};
+            if (this.segments.get(0).isNegative())
+                throw new QueryException(613, "Sequence is not allowed to be negative");
+        };
 
-	// The element may be expanded
-	if (this.segments.size() == 1 &&
-	    this.segments.get(0).isExtended() &&
-	    (this.hasConstraints() || !this.isInOrder())) {
-	    throw new QueryException(613, limitationError);
-	};
+        if (!this.isSolved) {
+            if (!_solveProblematicSequence()) {
+                if (this.segments.get(0).maybeExtension()) {
+                    throw new QueryException(
+                        613,
+                        "Sequence contains unresolvable " +
+                        "empty, optional, or negative segments"
+                    );
+                };
+            };
+        };
 
-	// Create the initial query
-	SpanQuery query = this.segments.get(0).toQuery();
+        // The element may be expanded
+        if (this.segments.size() == 1 &&
+            this.segments.get(0).isExtended() &&
+            (this.hasConstraints() || !this.isInOrder())) {
+            throw new QueryException(613, limitationError);
+        };
 
-	// NextQueries:
-	if (!this.hasConstraints() && this.isInOrder()) {
-	    for (int i = 1; i < this.segments.size(); i++) {
-		query = new SpanNextQuery(
-	            query,
-		    this.segments.get(i).toQuery()
-		);
-	    };
-	    return (SpanQuery) query;
-	};
+        // Create the initial query
+        SpanQuery query = null;// = this.segments.get(0).toQuery();
+        int i = 0;
+        while (query == null && i < this.segments.size()) {
+            query = this.segments.get(i).toQuery();
+            i++;
+        };
 
-	// DistanceQueries
-	if (this.constraints.size() == 1) {
-	    DistanceConstraint constraint = this.constraints.get(0);
+        if (query == null)
+            return (SpanQuery) null;
 
-	    // Create spanElementDistance query
-	    if (!constraint.getUnit().equals("w")) {
-		for (int i = 1; i < this.segments.size(); i++) {
+        // NextQueries:
+        if (!this.hasConstraints() && this.isInOrder()) {
+            for (; i < this.segments.size(); i++) {
 
-		    // No support for extended spans in constraints
-		    if (this.segments.get(i).isExtended())
-			throw new QueryException(613, limitationError);
+                SpanQuery second = this.segments.get(i).toQuery();
+                if (second == null)
+                    continue;
 
-		    SpanDistanceQuery sdquery = new SpanDistanceQuery(
-			    query,
-			    this.segments.get(i).toQuery(),
-			    constraint,
-			    true
-		    );
-		    query = (SpanQuery) sdquery;
-		};
-	    }
+                query = new SpanNextQuery(
+                    query,
+                    second
+                );
+            };
+            return (SpanQuery) query;
+        };
+        
+        // DistanceQueries
+        if (this.constraints.size() == 1) {
+            DistanceConstraint constraint = this.constraints.get(0);
 
-	    // Create spanDistance query
-	    else {
-		for (int i = 1; i < this.segments.size(); i++) {
+            // Create spanElementDistance query
+            if (!constraint.getUnit().equals("w")) {
+                for (i = 1; i < this.segments.size(); i++) {
 
-		    // No support for extended spans in constraints
-		    if (this.segments.get(i).isExtended())
-			throw new QueryException(613, limitationError);
+                    // No support for extended spans in constraints
+                    if (this.segments.get(i).isExtended())
+                        throw new QueryException(613, limitationError);
 
-		    SpanDistanceQuery sdquery = new SpanDistanceQuery(
-			query,
-			this.segments.get(i).toQuery(),
-			constraint,
-			true
-		    );
-		    query = (SpanQuery) sdquery;
-		};
-	    };
+                    SpanQuery sq = (SpanQuery) this.segments.get(i).toQuery();
+                    if (sq == null) continue;
 
-	    return (SpanQuery) query;
-	};
+                    SpanDistanceQuery sdquery = new SpanDistanceQuery(
+                        query,
+                        sq,
+                        constraint,
+                        true
+                    );
+                    query = (SpanQuery) sdquery;
+                };
+            }
 
-	// MultipleDistanceQueries
-	for (int i = 1; i < this.segments.size(); i++) {
+            // Create spanDistance query
+            else {
+                for (i = 1; i < this.segments.size(); i++) {
 
-	    // No support for extended spans in constraints
-	    if (this.segments.get(i).isExtended())
-		throw new QueryException(613, limitationError);
+                    // No support for extended spans in constraints
+                    if (this.segments.get(i).isExtended())
+                        throw new QueryException(613, limitationError);
 
-	    query = new SpanMultipleDistanceQuery(
-	        query,
-		this.segments.get(i).toQuery(),
-		this.constraints,
-		isInOrder,
-		true
-	    );
-	};
-	return (SpanQuery) query;
+                    SpanQuery sq = (SpanQuery) this.segments.get(i).toQuery();
+                    if (sq == null) continue;
+                    
+                    SpanDistanceQuery sdquery = new SpanDistanceQuery(
+                        query,
+                        sq,
+                        constraint,
+                        true
+                    );
+                    query = (SpanQuery) sdquery;
+                };
+            };
+
+            return (SpanQuery) query;
+        };
+
+        // MultipleDistanceQueries
+        for (i = 1; i < this.segments.size(); i++) {
+
+            // No support for extended spans in constraints
+            if (this.segments.get(i).isExtended())
+                throw new QueryException(613, limitationError);
+
+            SpanQuery sq = (SpanQuery) this.segments.get(i).toQuery();
+            if (sq == null) continue;
+
+            query = new SpanMultipleDistanceQuery(
+                query,
+                sq,
+                this.constraints,
+                isInOrder,
+                true
+	        );
+        };
+        return (SpanQuery) query;
     };
 
     /*
diff --git a/src/main/java/de/ids_mannheim/korap/query/wrap/SpanSubspanQueryWrapper.java b/src/main/java/de/ids_mannheim/korap/query/wrap/SpanSubspanQueryWrapper.java
index 2af6c19..25cf0d6 100644
--- a/src/main/java/de/ids_mannheim/korap/query/wrap/SpanSubspanQueryWrapper.java
+++ b/src/main/java/de/ids_mannheim/korap/query/wrap/SpanSubspanQueryWrapper.java
@@ -9,7 +9,7 @@
 import de.ids_mannheim.korap.util.QueryException;
 
 /**
- * @author margaretha
+ * @author margaretha, diewald
  * 
  */
 public class SpanSubspanQueryWrapper extends SpanQueryWrapper {
@@ -17,34 +17,114 @@
     private SpanQueryWrapper subquery;
     private int startOffset, length;
 
-    private Logger log = LoggerFactory.getLogger(SpanSubspanQueryWrapper.class);
+    private final static Logger log =
+        LoggerFactory.getLogger(SpanSubspanQueryWrapper.class);
 
-    public SpanSubspanQueryWrapper(SpanQueryWrapper sqw, int startOffset,
-            int length) {
+    // This advices the java compiler to ignore all loggings
+    public static final boolean DEBUG = false;
+
+    public SpanSubspanQueryWrapper(SpanQueryWrapper sqw,
+                                   int startOffset,
+                                   int length) {
         this.subquery = sqw;
+        if (sqw == null) {
+            this.isNull = true;
+            return;
+        }
+        else {
+            this.isNull = false;
+        };
+
         this.startOffset = startOffset;
         this.length = length;
+
+        // The embedded class is empty,
+        // but probably in a valid range
+        // - optimize
+        // subspan([]{,5}, 2) -> subspan([]{2,5}, 2)
+        // subspan([]{2,}, 2,5) -> subspan([]{2,5}, 2,5)
+        if (subquery.isEmpty()) {
+
+            // Todo: Is there a possible way to deal with that?
+            if (startOffset < 0) {
+                this.isNull = true;
+                return;
+            };
+
+            // e.g, subspan([]{0,6}, 8)
+            if (subquery.getMax() < startOffset) {
+                this.isNull = true;
+                return;
+            };
+
+            // Readjust the minimum of the subquery
+            if (startOffset > 0) {
+                subquery.setMin(startOffset);
+                subquery.isOptional = false;
+            };
+
+            // Readjust the maximum,
+            // although the following case may be somehow disputable:
+            // subspan([]{2,8}, 2, 1) -> subspan([]{2,5},2,1)
+            if (length > 0) {
+                int newMax = subquery.getMin() + startOffset + length;
+                if (subquery.getMax() > newMax) {
+                    subquery.setMax(subquery.getMin() + length);
+                };
+            };
+        };
+
+        // Todo: What happens with negative queries?
+        // submatch([base!=tree],3)
     }
 
     @Override
     public SpanQuery toQuery() throws QueryException {
-        if (subquery == null) {
-            log.warn("Subquery of SpanSubspanquery is null.");
+
+        if (this.isNull() || subquery.isNull()) {
+            if (DEBUG)
+                log.warn("Subquery of SpanSubspanquery is null.");
+            return null;
+        };
+
+        if (startOffset == 0 && length == 0) {
+            if (DEBUG)
+                log.warn("Not SpanSubspanQuery. Creating only the subquery.");
+            return subquery.toQuery();
+        };
+
+        // The embedded subquery may be null
+        SpanQuery sq = subquery.toQuery();
+        if (sq == null) return null;
+        
+        if (sq instanceof SpanTermQuery) {
+
+            // No relevant subspan
+            if ((startOffset == 0 || startOffset == -1) &&
+                (length <= 1)) {
+                if (DEBUG)
+                    log.warn("Not SpanSubspanQuery. " +
+                             "Creating only the subquery.");
+                return sq;
+            };
+
+            // Subspanquery can't match (always out of scope)
             return null;
         }
 
-        if (length == 0) {
-            log.warn("Not SpanSubspanQuery. Creating only the subquery.");
-            return subquery.toQuery();
-        }
-
-        SpanQuery sq = subquery.toQuery();
-        if (sq instanceof SpanTermQuery) {
-            log.warn("Not SpanSubspanQuery. Creating only the subquery.");
-            return sq;
-        }
-
-        return new SpanSubspanQuery(subquery.toQuery(), startOffset, length,
+        return new SpanSubspanQuery(sq, startOffset, length,
                 true);
     }
+
+    @Override
+    public boolean isNegative () {
+        return this.subquery.isNegative();
+    };
+
+    @Override
+    public boolean isOptional () {
+        if (startOffset > 0)
+            return false;
+        return this.subquery.isOptional();
+    };
 }
diff --git a/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTerm.java b/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTerm.java
index 14da689..b568fbe 100644
--- a/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTerm.java
+++ b/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTerm.java
@@ -16,107 +16,106 @@
 public class TestMultiTerm {
     @Test
     public void multiTermSimple () {
-	MultiTerm mt = new MultiTerm("test");
-	assertEquals(mt.term, "test");
-	assertNull(mt.payload);
-	assertEquals(mt.start, 0);
-	assertEquals(mt.end, 0);
+        MultiTerm mt = new MultiTerm("test");
+        assertEquals(mt.term, "test");
+        assertNull(mt.payload);
+        assertEquals(mt.start, 0);
+        assertEquals(mt.end, 0);
     };
 
     @Test
     public void multiTermPayload () {
-	MultiTerm mt = new MultiTerm("test$5");
-	assertEquals("test", mt.term);
-	assertEquals(new BytesRef("5"), mt.payload);
-	assertEquals(mt.start, 0);
-	assertEquals(mt.end, 0);
+        MultiTerm mt = new MultiTerm("test$5");
+        assertEquals("test", mt.term);
+        assertEquals(new BytesRef("5"), mt.payload);
+        assertEquals(mt.start, 0);
+        assertEquals(mt.end, 0);
     };
 
     @Test
     public void multiTermOffset () {
-	MultiTerm mt = new MultiTerm("versuch#2-34");
-	assertEquals(mt.term, "versuch");
-	assertNull(mt.payload);
-	assertEquals(mt.start, 2);
-	assertEquals(mt.end, 34);
+        MultiTerm mt = new MultiTerm("versuch#2-34");
+        assertEquals(mt.term, "versuch");
+        assertNull(mt.payload);
+        assertEquals(mt.start, 2);
+        assertEquals(mt.end, 34);
     };
 
     @Test
     public void multiTermOffsetPayload () {
-	MultiTerm mt = new MultiTerm("example#6-42$hihi");
-	assertEquals(mt.term, "example");
-	assertEquals(new BytesRef("hihi"), mt.payload);
-	assertEquals(mt.start,6);
-	assertEquals(mt.end, 42);
+        MultiTerm mt = new MultiTerm("example#6-42$hihi");
+        assertEquals(mt.term, "example");
+        assertEquals(new BytesRef("hihi"), mt.payload);
+        assertEquals(mt.start,6);
+        assertEquals(mt.end, 42);
     };
 
     @Test
     public void multiTermString () {
-	MultiTerm mt = new MultiTerm("example#6-42$hihi");
-	assertEquals("example#6-42$hihi", mt.toString());
-	mt.term = "spassmacher";
-	assertEquals("spassmacher#6-42$hihi", mt.toString());
+        MultiTerm mt = new MultiTerm("example#6-42$hihi");
+        assertEquals("example#6-42$hihi", mt.toString());
+        mt.term = "spassmacher";
+        assertEquals("spassmacher#6-42$hihi", mt.toString());
     };
 
     @Test
     public void multiTermStringPayloadType () {
-	MultiTerm mt = new MultiTerm("example$<i>4000");
-	assertEquals("example$<?>[0,0,f,a0]", mt.toString());
+        MultiTerm mt = new MultiTerm("example$<i>4000");
+        assertEquals("example$<?>[0,0,f,a0]", mt.toString());
 
-	mt = new MultiTerm("example$<l>757574643438");
-	assertEquals("example$<?>[0,0,0,b0,62,f7,ae,ee]", mt.toString());
+        mt = new MultiTerm("example$<l>757574643438");
+        assertEquals("example$<?>[0,0,0,b0,62,f7,ae,ee]", mt.toString());
     };
-
+    
     @Test
     public void multiTermStringPayloadType2 () {
-	MultiTerm mt = new MultiTerm();
-	mt.setTerm("beispiel");
-	mt.setStart(40);
-	assertEquals(mt.getStart(), mt.start);
-	mt.setEnd(50);
-	assertEquals(mt.getEnd(), mt.end);
-	mt.setPayload((int) 4000);
-	assertEquals("beispiel#40-50$<?>[0,0,f,a0]", mt.toString());
+        MultiTerm mt = new MultiTerm();
+        mt.setTerm("beispiel");
+        mt.setStart(40);
+        assertEquals(mt.getStart(), mt.start);
+        mt.setEnd(50);
+        assertEquals(mt.getEnd(), mt.end);
+        mt.setPayload((int) 4000);
+        assertEquals("beispiel#40-50$<?>[0,0,f,a0]", mt.toString());
     };
 
     @Test
     public void multiTermStringPayloadType3 () {
-	MultiTerm mt = new MultiTerm("example$<b>120");
-	assertEquals("example$x", mt.toString());
+        MultiTerm mt = new MultiTerm("example$<b>120");
+        assertEquals("example$x", mt.toString());
     };
 
     @Test
     public void multiTermStringPayloadType4 () {
-	MultiTerm mt = new MultiTerm("example$<i>420<b>120");
-	assertEquals("example$<?>[0,0,1,a4,78]", mt.toString());
+        MultiTerm mt = new MultiTerm("example$<i>420<b>120");
+        assertEquals("example$<?>[0,0,1,a4,78]", mt.toString());
     };
 
-
     @Test
     public void multiTermStringPayloadType5 () {
-	MultiTerm mt = new MultiTerm("example$<i>4000");
-	assertEquals("example$<?>[0,0,f,a0]", mt.toString());
+        MultiTerm mt = new MultiTerm("example$<i>4000");
+        assertEquals("example$<?>[0,0,f,a0]", mt.toString());
 
-	mt = new MultiTerm("example$<i>4000<b>120");
-	assertEquals("example$<?>[0,0,f,a0,78]", mt.toString());
+        mt = new MultiTerm("example$<i>4000<b>120");
+        assertEquals("example$<?>[0,0,f,a0,78]", mt.toString());
 
-	mt = new MultiTerm("example$<l>4000<b>120");
-	assertEquals("example$<?>[0,0,0,0,0,0,f,a0,78]", mt.toString());
+        mt = new MultiTerm("example$<l>4000<b>120");
+        assertEquals("example$<?>[0,0,0,0,0,0,f,a0,78]", mt.toString());
     };
 
     @Test
     public void multiTermStringFail () {
-	MultiTerm mt = new MultiTerm("example#56-66");
-	assertEquals(56, mt.getStart());
-	assertEquals(66,mt.getEnd());
+        MultiTerm mt = new MultiTerm("example#56-66");
+        assertEquals(56, mt.getStart());
+        assertEquals(66,mt.getEnd());
 
-	mt = new MultiTerm("example#56-66$<i>a");
-	assertEquals(56, mt.getStart());
-	assertEquals(66, mt.getEnd());
+        mt = new MultiTerm("example#56-66$<i>a");
+        assertEquals(56, mt.getStart());
+        assertEquals(66, mt.getEnd());
 
-	mt = new MultiTerm("example#56$<i>a");
-	assertEquals(mt.getPayload(), null);
-	assertEquals(mt.getStart(), 0);
-	assertEquals(mt.getEnd(), 0);
+        mt = new MultiTerm("example#56$<i>a");
+        assertEquals(mt.getPayload(), null);
+        assertEquals(mt.getStart(), 0);
+        assertEquals(mt.getEnd(), 0);
     };
 };
diff --git a/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTermToken.java b/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTermToken.java
index c3ab4c0..f88b194 100644
--- a/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTermToken.java
+++ b/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTermToken.java
@@ -14,27 +14,34 @@
 
 @RunWith(JUnit4.class)
 public class TestMultiTermToken {
+
     @Test
     public void multiTermTokenSimple () {
-	MultiTermToken mtt = new MultiTermToken("t:test", "a:abbruch");
-	assertEquals("[t:test|a:abbruch]", mtt.toString());
-	mtt.add("b:banane");
-	assertEquals("[t:test|a:abbruch|b:banane]", mtt.toString());
-	mtt.add("c:chaos#21-26");
-	assertEquals("[(21-26)t:test|a:abbruch|b:banane|c:chaos#21-26]", mtt.toString());
-	mtt.add("d:dadaismus#21-28$vergleich");
-	assertEquals("[(21-28)t:test|a:abbruch|b:banane|c:chaos#21-26|d:dadaismus#21-28$vergleich]", mtt.toString());
+        MultiTermToken mtt = new MultiTermToken("t:test", "a:abbruch");
+        assertEquals("[t:test|a:abbruch]", mtt.toString());
+        mtt.add("b:banane");
+        assertEquals("[t:test|a:abbruch|b:banane]", mtt.toString());
+        mtt.add("c:chaos#21-26");
+        assertEquals("[(21-26)t:test|a:abbruch|b:banane|c:chaos#21-26]",
+                     mtt.toString());
+        mtt.add("d:dadaismus#21-28$vergleich");
+        assertEquals(
+            "[(21-28)t:test|a:abbruch|b:banane|c:chaos#21-26|" +
+            "d:dadaismus#21-28$vergleich]",
+            mtt.toString()
+        );
     };
 
     @Test
     public void multiTermTokenOffsets () {
-	MultiTermToken mtt = new MultiTermToken("t:test#23-27");
-	assertEquals("[(23-27)t:test#23-27]", mtt.toString());
-	mtt.add("b:baum#34-45");
-	assertEquals("[(23-45)t:test#23-27|b:baum#34-45]", mtt.toString());
-	mtt.add("c:cannonball#34-45$tatsache");
-	assertEquals("[(23-45)t:test#23-27|b:baum#34-45|c:cannonball#34-45$tatsache]", mtt.toString());
-	assertEquals(23, mtt.start);
-	assertEquals(45, mtt.end);
+        MultiTermToken mtt = new MultiTermToken("t:test#23-27");
+        assertEquals("[(23-27)t:test#23-27]", mtt.toString());
+        mtt.add("b:baum#34-45");
+        assertEquals("[(23-45)t:test#23-27|b:baum#34-45]", mtt.toString());
+        mtt.add("c:cannonball#34-45$tatsache");
+        assertEquals("[(23-45)t:test#23-27|b:baum#34-45|" +
+                     "c:cannonball#34-45$tatsache]", mtt.toString());
+        assertEquals(23, mtt.start);
+        assertEquals(45, mtt.end);
     };
 };
diff --git a/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTermTokenStream.java b/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTermTokenStream.java
index c5b15c0..ff20192 100644
--- a/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTermTokenStream.java
+++ b/src/test/java/de/ids_mannheim/korap/analysis/TestMultiTermTokenStream.java
Binary files differ
diff --git a/src/test/java/de/ids_mannheim/korap/benchmark/TestBenchmarkSpans.java b/src/test/java/de/ids_mannheim/korap/benchmark/TestBenchmarkSpans.java
index 6e85f27..1a28f7d 100644
--- a/src/test/java/de/ids_mannheim/korap/benchmark/TestBenchmarkSpans.java
+++ b/src/test/java/de/ids_mannheim/korap/benchmark/TestBenchmarkSpans.java
@@ -27,357 +27,353 @@
 
     @Test
     public void checkBenchmark1 () throws IOException {
-	Properties prop = new Properties();
-	InputStream fr = new FileInputStream(getClass().getResource("/korap.conf").getFile());
-	prop.load(fr);
+        Properties prop = new Properties();
+        InputStream fr = new FileInputStream(getClass().getResource("/korap.conf").getFile());
+        prop.load(fr);
 
-	// Get the real index
-	KorapIndex ki = new KorapIndex(new MMapDirectory(new File(prop.getProperty("lucene.indexDir"))));
+        // Get the real index
+        KorapIndex ki = new KorapIndex(new MMapDirectory(new File(prop.getProperty("lucene.indexDir"))));
 
-	// Create a container for virtual collections:
-	KorapCollection kc = new KorapCollection(ki);
+        // Create a container for virtual collections:
+        KorapCollection kc = new KorapCollection(ki);
 
-	long t1 = 0, t2 = 0;
-	/// cosmas20.json!!!
-	String json = getString(getClass().getResource("/queries/benchmark1.jsonld").getFile());
+        long t1 = 0, t2 = 0;
+        /// cosmas20.json!!!
+        String json = getString(getClass().getResource("/queries/benchmark1.jsonld").getFile());
 
-	int rounds = 100;
+        int rounds = 100;
 
-	KorapResult kr = new KorapResult();
+        KorapResult kr = new KorapResult();
 
-	t1 = System.nanoTime();
-	for (int i = 1; i <= rounds; i++) {
-	    kr = new KorapSearch(json).run(ki);
-	};
-	t2 = System.nanoTime();
+        t1 = System.nanoTime();
+        for (int i = 1; i <= rounds; i++) {
+            kr = new KorapSearch(json).run(ki);
+        };
+        t2 = System.nanoTime();
 
-	// assertEquals("TotalResults", 30751, kr.getTotalResults());
-	assertEquals("TotalResults",  kr.getTotalResults(), 4803739);
+        // assertEquals("TotalResults", 30751, kr.getTotalResults());
+        assertEquals("TotalResults",  kr.getTotalResults(), 4803739);
 
-	// System.err.println(kr.toJSON());
-
-
-	//	long seconds = (long) (t2 - t1 / 1000) % 60 ;
-	double seconds = (double)(t2-t1) / 1000000000.0;
+        //	long seconds = (long) (t2 - t1 / 1000) % 60 ;
+        double seconds = (double)(t2-t1) / 1000000000.0;
 	
-	System.out.println("It took " + seconds + " seconds");
+        // System.out.println("It took " + seconds + " seconds");
 
-	// 100 times:
-	// 43,538 sec
-	// 4.874
+        // 100 times:
+        // 43,538 sec
+        // 4.874
+        
+        // 1000 times:
+        // 36.613 sec
 
-	// 1000 times:
-	// 36.613 sec
-
-
-	// After refactoring
-	// 100 times
-	// 273.58114372 seconds
-
-	// After intro of attributes
-	// 100 times
-	// 350.171506379 seconds
+        // After refactoring
+        // 100 times
+        // 273.58114372 seconds
+        
+        // After intro of attributes
+        // 100 times
+        // 350.171506379 seconds
     };
 
 
     @Test
     public void checkBenchmark2JSON () throws IOException {
-	Properties prop = new Properties();
-	InputStream fr = new FileInputStream(getClass().getResource("/korap.conf").getFile());
-	prop.load(fr);
+        Properties prop = new Properties();
+        InputStream fr = new FileInputStream(getClass().getResource("/korap.conf").getFile());
+        prop.load(fr);
 
-	// Get the real index
-	KorapIndex ki = new KorapIndex(new MMapDirectory(new File(prop.getProperty("lucene.indexDir"))));
+        // Get the real index
+        KorapIndex ki = new KorapIndex(new MMapDirectory(new File(prop.getProperty("lucene.indexDir"))));
+        
+        // Create a container for virtual collections:
+        KorapCollection kc = new KorapCollection(ki);
 
-	// Create a container for virtual collections:
-	KorapCollection kc = new KorapCollection(ki);
+        long t1 = 0, t2 = 0;
+        /// cosmas20.json!!!
+        String json = getString(getClass().getResource("/queries/benchmark2.jsonld").getFile());
+        
+        int rounds = 10000;
+        
+        KorapResult kr = new KorapResult();
+        String result = new String("");
+        
+        t1 = System.nanoTime();
+        double length = 0;
+        for (int i = 1; i <= rounds; i++) {
+            kr = new KorapSearch(json).run(ki);
+            length += kr.toJsonString().length();
+        };
+        t2 = System.nanoTime();
 
-	long t1 = 0, t2 = 0;
-	/// cosmas20.json!!!
-	String json = getString(getClass().getResource("/queries/benchmark2.jsonld").getFile());
+        //	assertEquals("TotalResults", 30751, kr.getTotalResults());
 
-	int rounds = 10000;
+        // System.err.println(kr.toJSON());
 
-	KorapResult kr = new KorapResult();
-	String result = new String("");
-
-	t1 = System.nanoTime();
-	double length = 0;
-	for (int i = 1; i <= rounds; i++) {
-	    kr = new KorapSearch(json).run(ki);
-	    length += kr.toJsonString().length();
-	};
-	t2 = System.nanoTime();
-
-	//	assertEquals("TotalResults", 30751, kr.getTotalResults());
-
-	// System.err.println(kr.toJSON());
-
-	//	long seconds = (long) (t2 - t1 / 1000) % 60 ;
-	double seconds = (double)(t2-t1) / 1000000000.0;
+        //	long seconds = (long) (t2 - t1 / 1000) % 60 ;
+        double seconds = (double)(t2-t1) / 1000000000.0;
 	
-	System.out.println("It took " + seconds + " seconds");
+        // System.out.println("It took " + seconds + " seconds");
 
-	// 10000 times:
-	//  77.167124985 sec
+        // 10000 times:
+        //  77.167124985 sec
     };
 
 
     @Test
     public void checkBenchmarkSentences () throws IOException {
-	Properties prop = new Properties();
-	InputStream fr = new FileInputStream(getClass().getResource("/korap.conf").getFile());
-	prop.load(fr);
+        Properties prop = new Properties();
+        InputStream fr = new FileInputStream(getClass().getResource("/korap.conf").getFile());
+        prop.load(fr);
 
-	// Get the real index
-	KorapIndex ki = new KorapIndex(new MMapDirectory(new File(prop.getProperty("lucene.indexDir"))));
+        // Get the real index
+        KorapIndex ki = new KorapIndex(new MMapDirectory(new File(prop.getProperty("lucene.indexDir"))));
 
-	// Create a container for virtual collections:
-	KorapCollection kc = new KorapCollection(ki);
+        // Create a container for virtual collections:
+        KorapCollection kc = new KorapCollection(ki);
 
-	long t1 = 0, t2 = 0;
-	/// cosmas20.json!!!
-	String json = getString(getClass().getResource("/queries/benchmark4.jsonld").getFile());
+        long t1 = 0, t2 = 0;
+        /// cosmas20.json!!!
+        String json = getString(getClass().getResource("/queries/benchmark4.jsonld").getFile());
 
-	int rounds = 10;
+        int rounds = 10;
 
-	KorapResult kr = new KorapResult();
+        KorapResult kr = new KorapResult();
 
-	t1 = System.nanoTime();
-	double length = 0;
-	for (int i = 1; i <= rounds; i++) {
-	    kr = new KorapSearch(json).run(ki);
-	};
-	t2 = System.nanoTime();
+        t1 = System.nanoTime();
+        double length = 0;
+        for (int i = 1; i <= rounds; i++) {
+            kr = new KorapSearch(json).run(ki);
+        };
+        t2 = System.nanoTime();
 
-	// System.err.println(kr.getMatch(0).toJSON());
+        // System.err.println(kr.getMatch(0).toJSON());
+        
+        assertEquals("TotalResults1", kr.getTotalResults(), 4116282);
+        assertEquals("TotalResults2", kr.getTotalResults(), ki.numberOf("sentences"));
 
-	assertEquals("TotalResults1", kr.getTotalResults(), 4116282);
-	assertEquals("TotalResults2", kr.getTotalResults(), ki.numberOf("sentences"));
-
-	double seconds = (double)(t2-t1) / 1000000000.0;
-	
-	System.out.println("It took " + seconds + " seconds");
-	// 100 rounds
-	// 56.253 secs
+        double seconds = (double)(t2-t1) / 1000000000.0;
+        
+        // System.out.println("It took " + seconds + " seconds");
+        // 100 rounds
+        // 56.253 secs
     };
 
     
     @Test
     public void checkBenchmarkClasses () throws IOException {
-	// [orth=Der]{1:[orth=Mann]{2:[orth=und]}}
+        // [orth=Der]{1:[orth=Mann]{2:[orth=und]}}
 
-	Properties prop = new Properties();
-	InputStream fr = new FileInputStream(getClass().getResource("/korap.conf").getFile());
-	prop.load(fr);
+        Properties prop = new Properties();
+        InputStream fr = new FileInputStream(getClass().getResource("/korap.conf").getFile());
+        prop.load(fr);
 
-	// Get the real index
-	KorapIndex ki = new KorapIndex(new MMapDirectory(new File(prop.getProperty("lucene.indexDir"))));
+        // Get the real index
+        KorapIndex ki = new KorapIndex(new MMapDirectory(new File(prop.getProperty("lucene.indexDir"))));
 
-	// Create a container for virtual collections:
-	KorapCollection kc = new KorapCollection(ki);
+        // Create a container for virtual collections:
+        KorapCollection kc = new KorapCollection(ki);
 
-	long t1 = 0, t2 = 0;
-	// Without classes
-	String json = getString(getClass().getResource("/queries/benchmark5-ohne.jsonld").getFile());
+        long t1 = 0, t2 = 0;
+        // Without classes
+        String json = getString(getClass().getResource("/queries/benchmark5-ohne.jsonld").getFile());
 
-	int rounds = 2000;
+        int rounds = 2000;
+        
+        KorapResult kr = new KorapResult();
 
-	KorapResult kr = new KorapResult();
+        t1 = System.nanoTime();
+        for (int i = 1; i <= rounds; i++) {
+            kr = new KorapSearch(json).run(ki);
+        };
+        t2 = System.nanoTime();
 
-	t1 = System.nanoTime();
-	for (int i = 1; i <= rounds; i++) {
-	    kr = new KorapSearch(json).run(ki);
-	};
-	t2 = System.nanoTime();
+        double seconds = (double)(t2-t1) / 1000000000.0;
+        
+        // System.out.println("It took " + seconds + " seconds without classes");
 
-	double seconds = (double)(t2-t1) / 1000000000.0;
-	
-	System.out.println("It took " + seconds + " seconds without classes");
+        t1 = 0;
+        t2 = 0;
+        // With classes
+        json = getString(getClass().getResource("/queries/benchmark5.jsonld").getFile());
+        
+        t1 = System.nanoTime();
+        for (int i = 1; i <= rounds; i++) {
+            kr = new KorapSearch(json).run(ki);
+        };
+        t2 = System.nanoTime();
 
-	t1 = 0;
-	t2 = 0;
-	// With classes
-	json = getString(getClass().getResource("/queries/benchmark5.jsonld").getFile());
+        seconds = (double)(t2-t1) / 1000000000.0;
+        
+        // System.out.println("It took " + seconds + " seconds with classes");
 
-	t1 = System.nanoTime();
-	for (int i = 1; i <= rounds; i++) {
-	    kr = new KorapSearch(json).run(ki);
-	};
-	t2 = System.nanoTime();
+        t1 = 0;
+        t2 = 0;
+        // With submatch
+        json = getString(getClass().getResource("/queries/benchmark5-submatch.jsonld").getFile());
 
-	seconds = (double)(t2-t1) / 1000000000.0;
-	
-	System.out.println("It took " + seconds + " seconds with classes");
+        t1 = System.nanoTime();
+        for (int i = 1; i <= rounds; i++) {
+            kr = new KorapSearch(json).run(ki);
+        };
+        t2 = System.nanoTime();
 
-	t1 = 0;
-	t2 = 0;
-	// With submatch
-	json = getString(getClass().getResource("/queries/benchmark5-submatch.jsonld").getFile());
+        seconds = (double)(t2-t1) / 1000000000.0;
+        
+        // System.out.println("It took " + seconds + " seconds with submatches");
 
-	t1 = System.nanoTime();
-	for (int i = 1; i <= rounds; i++) {
-	    kr = new KorapSearch(json).run(ki);
-	};
-	t2 = System.nanoTime();
+        /** HERE IS A BUG! */
+        
+        // System.err.println(kr.toJsonString());
 
-	seconds = (double)(t2-t1) / 1000000000.0;
-	
-	System.out.println("It took " + seconds + " seconds with submatches");
+        // System.err.println(kr.toJSON());
 
-	/** HERE IS A BUG! */
-
-	System.err.println(kr.toJsonString());
+        // System.err.println(kr.getMatch(3).getSnippetBrackets());
 
 
+        // 2000 rounds:
+        // It took 10.872934435 seconds without classes
+        // It took 22.581117396 seconds with classes
 
-	// System.err.println(kr.toJSON());
+        // It took 10.703933598 seconds without classes
+        // It took 19.354674517 seconds with classes
 
-	// System.err.println(kr.getMatch(3).getSnippetBrackets());
+        // It took 10.939948726 seconds without classes
+        // It took 16.998470662 seconds with classes
 
+        // It took 10.900975837 seconds without classes
+        // It took 14.902590949 seconds with classes
 
-	// 2000 rounds:
-	// It took 10.872934435 seconds without classes
-	// It took 22.581117396 seconds with classes
+        // It took 10.365989238 seconds without classes
+        // It took 13.833405885 seconds with classes
 
-	// It took 10.703933598 seconds without classes
-	// It took 19.354674517 seconds with classes
-
-	// It took 10.939948726 seconds without classes
-	// It took 16.998470662 seconds with classes
-
-	// It took 10.900975837 seconds without classes
-	// It took 14.902590949 seconds with classes
-
-	// It took 10.365989238 seconds without classes
-	// It took 13.833405885 seconds with classes
-
-	// It took 15.368675425 seconds without classes
-	// It took 18.347603186 seconds with classes
-	// It took 15.941057294 seconds with submatches
-
-	// It took 15.241253549 seconds without classes
-	// It took 17.30375624 seconds with classes
-	// It took 15.367171254 seconds with submatches
+        // It took 15.368675425 seconds without classes
+        // It took 18.347603186 seconds with classes
+        // It took 15.941057294 seconds with submatches
+        
+        // It took 15.241253549 seconds without classes
+        // It took 17.30375624 seconds with classes
+        // It took 15.367171254 seconds with submatches
     };
 
-
-
-    
     @Test
     public void checkBenchmarkIndexDocuments () throws IOException {
-	long t1 = 0, t2 = 0;
+        long t1 = 0, t2 = 0;
 
-	int rounds = 10;
+        int rounds = 10;
 
-	ArrayList<String> docs = new ArrayList<String>(700);
+        ArrayList<String> docs = new ArrayList<String>(700);
 
-	for (int a = 0; a < 50; a++) {
-	    for (String d : new String[] {"00001", "00002", "00003",
-				   "00004", "00005", "00006", "02439"}) {
-		docs.add(d);
-	    };
-	};
+        for (int a = 0; a < 50; a++) {
+            for (String d : new String[] {
+                    "00001",
+                    "00002",
+                    "00003",
+                    "00004",
+                    "00005",
+                    "00006",
+                    "02439"}) {
+                docs.add(d);
+            };
+        };
 
-	t1 = System.nanoTime();
-	double length = 0;
-	for (int i = 1; i <= rounds; i++) {
-	    // Construct index
-	    KorapIndex ki = new KorapIndex();
+        t1 = System.nanoTime();
+        double length = 0;
+        for (int i = 1; i <= rounds; i++) {
+            // Construct index
+            KorapIndex ki = new KorapIndex();
+            
+            // Indexing test files
+            for (String d : docs) {
+                FieldDocument fd = ki.addDocFile(
+                    getClass().getResource("/wiki/" + d + ".json.gz").getFile(),
+                    true
+                );
+            };
+            ki.commit();
+        };
+        t2 = System.nanoTime();
 
-	    // Indexing test files
-	    for (String d : docs) {
-		FieldDocument fd = ki.addDocFile(
-		    getClass().getResource("/wiki/" + d + ".json.gz").getFile(),
-		    true
-		);
-	    };
-	    ki.commit();
-	};
-	t2 = System.nanoTime();
+        double seconds = (double)(t2-t1) / 1000000000.0;
+        // System.out.println("It took " + seconds + " seconds");
 
-	double seconds = (double)(t2-t1) / 1000000000.0;
-	System.out.println("It took " + seconds + " seconds");
-
-	// 10 times / 350 docs:
-	// 36.26158006 seconds
-	// 32.52575097 seconds
-	// 31.818091536 seconds
-	// 32.055321123 seconds
-	// 32.32125959 seconds
-	// 31.726277979 seconds
-	// 31.65826188 seconds
-	// 31.287057537 seconds
+        // 10 times / 350 docs:
+        // 36.26158006 seconds
+        // 32.52575097 seconds
+        // 31.818091536 seconds
+        // 32.055321123 seconds
+        // 32.32125959 seconds
+        // 31.726277979 seconds
+        // 31.65826188 seconds
+        // 31.287057537 seconds
     };
 
 
     @Test
     public void checkBenchmark3 () throws IOException {
-	Properties prop = new Properties();
-	InputStream fr = new FileInputStream(getClass().getResource("/korap.conf").getFile());
-	prop.load(fr);
+        Properties prop = new Properties();
+        InputStream fr = new FileInputStream(getClass().getResource("/korap.conf").getFile());
+        prop.load(fr);
 
-	// Get the real index
-	KorapIndex ki = new KorapIndex(new MMapDirectory(new File(prop.getProperty("lucene.indexDir"))));
+        // Get the real index
+        KorapIndex ki = new KorapIndex(new MMapDirectory(new File(prop.getProperty("lucene.indexDir"))));
 
-	// Create a container for virtual collections:
-	KorapCollection kc = new KorapCollection(ki);
+        // Create a container for virtual collections:
+        KorapCollection kc = new KorapCollection(ki);
 
-	long t1 = 0, t2 = 0;
-	/// cosmas20.json!!!
-	String json = getString(getClass().getResource("/queries/benchmark3.jsonld").getFile());
+        long t1 = 0, t2 = 0;
+        /// cosmas20.json!!!
+        String json = getString(getClass().getResource("/queries/benchmark3.jsonld").getFile());
 
-	int rounds = 500;
+        int rounds = 500;
+    
+        KorapResult kr = new KorapResult();
 
-	KorapResult kr = new KorapResult();
+        t1 = System.nanoTime();
+        for (int i = 1; i <= rounds; i++) {
+            kr = new KorapSearch(json).run(ki);
+        };
+        t2 = System.nanoTime();
 
-	t1 = System.nanoTime();
-	for (int i = 1; i <= rounds; i++) {
-	    kr = new KorapSearch(json).run(ki);
-	};
-	t2 = System.nanoTime();
+        assertEquals("TotalResults", kr.getTotalResults(), 70229);
 
-	assertEquals("TotalResults", kr.getTotalResults(), 70229);
+        // System.err.println(kr.toJSON());
 
-	// System.err.println(kr.toJSON());
-
-	//	long seconds = (long) (t2 - t1 / 1000) % 60 ;
-	double seconds = (double)(t2-t1) / 1000000000.0;
+        //	long seconds = (long) (t2 - t1 / 1000) % 60 ;
+        double seconds = (double)(t2-t1) / 1000000000.0;
 	
-	System.out.println("It took " + seconds + " seconds");
+        System.out.println("It took " + seconds + " seconds");
 
-	// 500 times:
-	// 71.715862716 seconds
+        // 500 times:
+        // 71.715862716 seconds
     };
 
 
     public static String getString (String path) {
-	StringBuilder contentBuilder = new StringBuilder();
-	try {
-	    BufferedReader in = new BufferedReader(new FileReader(path));
-	    String str;
-	    while ((str = in.readLine()) != null) {
-		contentBuilder.append(str);
-	    };
-	    in.close();
-	} catch (IOException e) {
-	    fail(e.getMessage());
-	}
-	return contentBuilder.toString();
-    };
-
-    public static SpanQueryWrapper jsonQuery (String jsonFile) {
-	SpanQueryWrapper sqwi;
-	
-	try {
-	    String json = getString(jsonFile);
-	    sqwi = new KorapQuery("tokens").fromJson(json);
-	}
-	catch (QueryException e) {
-	    fail(e.getMessage());
-	    sqwi = new KorapQuery("tokens").seg("???");
-	};
-	return sqwi;
+        StringBuilder contentBuilder = new StringBuilder();
+        try {
+            BufferedReader in = new BufferedReader(new FileReader(path));
+            String str;
+            while ((str = in.readLine()) != null) {
+                contentBuilder.append(str);
+            };
+            in.close();
+        } catch (IOException e) {
+            fail(e.getMessage());
+        }
+        return contentBuilder.toString();
     };
     
+    public static SpanQueryWrapper jsonQuery (String jsonFile) {
+        SpanQueryWrapper sqwi;
+	
+        try {
+            String json = getString(jsonFile);
+            sqwi = new KorapQuery("tokens").fromJson(json);
+        }
+        catch (QueryException e) {
+            fail(e.getMessage());
+            sqwi = new KorapQuery("tokens").seg("???");
+        };
+        return sqwi;
+    };
 };
diff --git a/src/test/java/de/ids_mannheim/korap/query/TestSpanSubspanQueryJSON.java b/src/test/java/de/ids_mannheim/korap/query/TestSpanSubspanQueryJSON.java
index c9f6d56..342a90f 100644
--- a/src/test/java/de/ids_mannheim/korap/query/TestSpanSubspanQueryJSON.java
+++ b/src/test/java/de/ids_mannheim/korap/query/TestSpanSubspanQueryJSON.java
@@ -10,14 +10,13 @@
 import de.ids_mannheim.korap.util.QueryException;
 
 /**
- * @author margaretha
- * 
+ * @author margaretha, diewald
  */
 public class TestSpanSubspanQueryJSON {
 
     @Test
     public void testCase1() throws QueryException {
-        String filepath = getClass().getResource("/queries/submatch.jsonld")
+        String filepath = getClass().getResource("/queries/submatch/1.jsonld")
                 .getFile();
         SpanQueryWrapper sqwi = getJSONQuery(filepath);
         SpanQuery sq = sqwi.toQuery();
@@ -27,20 +26,58 @@
 
     @Test
     public void testCase2() throws QueryException {
-        String filepath = getClass().getResource("/queries/submatch2.jsonld")
-                .getFile();
+        String filepath = getClass().getResource("/queries/submatch/2.jsonld")
+            .getFile();
         SpanQueryWrapper sqwi = getJSONQuery(filepath);
         SpanQuery sq = sqwi.toQuery();
         assertEquals(sq.toString(), "subspan(<tokens:s />,1,4)");
     }
 
+    @Test
     public void testCase3() throws QueryException {
-        String filepath = getClass().getResource("/queries/submatch3.jsonld")
+        String filepath = getClass().getResource("/queries/submatch/3.jsonld")
                 .getFile();
         SpanQueryWrapper sqwi = getJSONQuery(filepath);
         SpanQuery sq = sqwi.toQuery();
         assertEquals(sq.toString(), "subspan(<tokens:s />,1,0)");
-
     }
 
+    @Test
+    public void testCaseWrapped() throws QueryException {
+        String filepath = getClass().getResource("/queries/submatch/wrapped.jsonld")
+                .getFile();
+        SpanQueryWrapper sqwi = getJSONQuery(filepath);
+        SpanQuery sq = sqwi.toQuery();
+        assertEquals(sq.toString(), "shrink(129: spanElementDistance({129: tokens:s:der},"+
+                     " {129: subspan(<tokens:s />,0,1)}, [(s[0:0], ordered, notExcluded)]))");
+    }
+
+
+    @Test
+    public void testCaseEmbedded() throws QueryException {
+        String filepath = getClass().getResource("/queries/submatch/embedded.jsonld")
+                .getFile();
+        SpanQueryWrapper sqwi = getJSONQuery(filepath);
+        SpanQuery sq = sqwi.toQuery();
+        assertEquals(sq.toString(), "spanNext({1: tokens:s:die},"+
+                     " {1: subspan(spanExpansion(tokens:s:der, []{1, 100}, right),2,3)})");
+    }
+
+    @Test
+    public void testCaseEmbeddedNull() throws QueryException {
+        String filepath = getClass().getResource("/queries/submatch/embedded-null.jsonld")
+                .getFile();
+        SpanQueryWrapper sqwi = getJSONQuery(filepath);
+        SpanQuery sq = sqwi.toQuery();
+        assertEquals(sq.toString(), "tokens:s:die");
+    }
+
+    @Test
+    public void testCaseEmbeddedValidEmpty() throws QueryException {
+        String filepath = getClass().getResource("/queries/submatch/embedded-valid-empty.jsonld")
+                .getFile();
+        SpanQueryWrapper sqwi = getJSONQuery(filepath);
+        SpanQuery sq = sqwi.toQuery();
+        assertEquals(sq.toString(), "??? (Known issue)");
+    }
 }
diff --git a/src/test/resources/queries/submatch.jsonld b/src/test/resources/queries/submatch/1.jsonld
similarity index 100%
rename from src/test/resources/queries/submatch.jsonld
rename to src/test/resources/queries/submatch/1.jsonld
diff --git a/src/test/resources/queries/submatch2.jsonld b/src/test/resources/queries/submatch/2.jsonld
similarity index 100%
rename from src/test/resources/queries/submatch2.jsonld
rename to src/test/resources/queries/submatch/2.jsonld
diff --git a/src/test/resources/queries/submatch3.jsonld b/src/test/resources/queries/submatch/3.jsonld
similarity index 100%
rename from src/test/resources/queries/submatch3.jsonld
rename to src/test/resources/queries/submatch/3.jsonld
diff --git a/src/test/resources/queries/submatch/embedded-null.jsonld b/src/test/resources/queries/submatch/embedded-null.jsonld
new file mode 100644
index 0000000..4672473
--- /dev/null
+++ b/src/test/resources/queries/submatch/embedded-null.jsonld
@@ -0,0 +1,39 @@
+{
+  "@context":"http://ids-mannheim.de/ns/KorAP/json-ld/v0.2/context.jsonld",
+  "collection":null,
+  "query" : {
+    "@type" : "korap:group",
+    "operation":"operation:sequence",
+    "operands" : [
+      {
+        "@type" : "korap:token",
+        "wrap" : {
+          "@type" : "korap:term",
+          "foundry" : "opennlp",
+          "key" : "die",
+          "layer" : "orth",
+          "match" : "match:eq"
+        }
+      },
+      {
+        "@type" : "korap:group",
+        "operands" : [
+          {
+            "@type" : "korap:reference",
+	    "operands" : [
+	      {
+		"@type" : "korap:token"
+	      }
+	    ],
+            "operation" : "operation:focus",
+            "spanRef" : [
+              5,
+              6
+            ]
+          }
+        ],
+        "operation" : "operation:class"
+      }
+    ]
+  }
+}
diff --git a/src/test/resources/queries/submatch/embedded-valid-empty.jsonld b/src/test/resources/queries/submatch/embedded-valid-empty.jsonld
new file mode 100644
index 0000000..a6f22bd
--- /dev/null
+++ b/src/test/resources/queries/submatch/embedded-valid-empty.jsonld
@@ -0,0 +1,40 @@
+{
+  "@context":"http://ids-mannheim.de/ns/KorAP/json-ld/v0.2/context.jsonld",
+  "collection":null,
+  "query" : {
+    "@type" : "korap:group",
+    "operation":"operation:sequence",
+    "operands" : [
+      {
+        "@type" : "korap:token",
+        "wrap" : {
+          "@type" : "korap:term",
+          "foundry" : "opennlp",
+          "key" : "die",
+          "layer" : "orth",
+          "match" : "match:eq"
+        }
+      },
+      {
+        "@type" : "korap:reference",
+        "spanRef" : [2],
+	"operands" : [
+	  {
+	    "@type" : "korap:group",
+	    "operation" : "operation:repetition",
+	    "boundary" : {
+	      "@type" : "korap:boundary",
+	      "max" : 5,
+	      "min" : 0
+	    },
+	    "operands" : [
+	      {
+		"@type" : "korap:token"
+	      }
+	    ]
+	  }
+	]
+      }
+    ]
+  }
+}
diff --git a/src/test/resources/queries/submatch/embedded.jsonld b/src/test/resources/queries/submatch/embedded.jsonld
new file mode 100644
index 0000000..e09bef5
--- /dev/null
+++ b/src/test/resources/queries/submatch/embedded.jsonld
@@ -0,0 +1,71 @@
+{
+  "@context":"http://ids-mannheim.de/ns/KorAP/json-ld/v0.2/context.jsonld",
+  "collection":null,
+  "query" : {
+    "@type" : "korap:group",
+    "operands" : [
+      {
+        "@type" : "korap:group",
+        "operands" : [
+          {
+            "@type" : "korap:token",
+            "wrap" : {
+              "@type" : "korap:term",
+              "foundry" : "opennlp",
+              "key" : "die",
+              "layer" : "orth",
+              "match" : "match:eq"
+            }
+          }
+        ],
+        "operation" : "operation:class"
+      },
+      {
+        "@type" : "korap:group",
+        "operands" : [
+          {
+            "@type" : "korap:reference",
+            "operands" : [
+	      {
+		"@type" : "korap:group",
+		"operands" : [
+		  {
+		    "@type" : "korap:token",
+		    "wrap" : {
+		      "@type" : "korap:term",
+		      "foundry" : "opennlp",
+		      "key" : "der",
+		      "layer" : "orth",
+		      "match" : "match:eq"
+		    }
+		  },
+		  {
+		    "@type" : "korap:group",
+		    "boundary" : {
+		      "@type" : "korap:boundary",
+		      "min" : 1
+		    },
+		    "operands" : [
+		      {
+			"@type" : "korap:token"
+		      }
+		    ],
+		    "operation" : "operation:repetition"
+		  }
+		],
+		"operation" : "operation:sequence"
+	      }
+            ],
+            "operation" : "operation:focus",
+            "spanRef" : [
+              2,
+              3
+            ]
+          }
+        ],
+        "operation" : "operation:class"
+      }
+    ],
+    "operation" : "operation:sequence"
+  }
+}
diff --git a/src/test/resources/queries/submatch/wrapped.jsonld b/src/test/resources/queries/submatch/wrapped.jsonld
new file mode 100644
index 0000000..8bc7b0c
--- /dev/null
+++ b/src/test/resources/queries/submatch/wrapped.jsonld
@@ -0,0 +1,73 @@
+{
+  "@context":"http://ids-mannheim.de/ns/KorAP/json-ld/v0.2/context.jsonld",
+  "collection":null,
+  "query" : {
+    "@type" : "korap:reference",
+    "classRef" : [
+      129
+    ],
+    "operands" : [
+      {
+        "@type" : "korap:group",
+        "distances" : [
+          {
+            "@type" : "cosmas:distance",
+            "boundary" : {
+              "@type" : "korap:boundary",
+              "max" : 0,
+              "min" : 0
+            },
+            "key" : "s",
+            "max" : 0,
+            "min" : 0
+          }
+        ],
+        "inOrder" : true,
+        "operands" : [
+          {
+            "@type" : "korap:group",
+            "class" : 129,
+            "classOut" : 129,
+            "operands" : [
+              {
+                "@type" : "korap:token",
+                "wrap" : {
+                  "@type" : "korap:term",
+                  "foundry" : "opennlp",
+                  "key" : "der",
+                  "layer" : "orth",
+                  "match" : "match:eq"
+                }
+              }
+            ],
+            "operation" : "operation:class"
+          },
+          {
+            "@type" : "korap:group",
+            "class" : 129,
+            "classOut" : 129,
+            "operands" : [
+              {
+                "@type" : "korap:reference",
+                "operands" : [
+                  {
+                    "@type" : "korap:span",
+                    "key" : "s"
+                  }
+                ],
+                "operation" : "operation:focus",
+                "spanRef" : [
+                  0,
+                  1
+                ]
+              }
+            ],
+            "operation" : "operation:class"
+          }
+        ],
+        "operation" : "operation:sequence"
+      }
+    ],
+    "operation" : "operation:focus"
+  }
+}