diff --git a/src/main/java/de/ids_mannheim/korap/query/SpanAttributeQuery.java b/src/main/java/de/ids_mannheim/korap/query/SpanAttributeQuery.java
index 150f060..bf7ce85 100644
--- a/src/main/java/de/ids_mannheim/korap/query/SpanAttributeQuery.java
+++ b/src/main/java/de/ids_mannheim/korap/query/SpanAttributeQuery.java
@@ -13,61 +13,118 @@
 
 import de.ids_mannheim.korap.query.spans.AttributeSpans;
 
-/** Span enumerations of attributes (i.e. spans with prefix @, for example 
- * 	@:class=header) commonly used to search elements with some specific 
- * 	attribute(s). Negation allows for searching element <em>without</em> some 
- * 	attribute(s). 
+/**
+ * SpanAttributeQuery retrieves attribute spans, that are tokens annotated with
+ * prefix @, for example {@literal @}:class=header. SpanAttributeQueries are
+ * commonly used to search for elements or relations having some specific
+ * attribute(s).
  * 
- * 	@author margaretha
+ * Example: <br/>
+ * <br/>
+ * 
+ * <pre>
+ * SpanAttributeQuery saq = new SpanAttributeQuery(new SpanTermQuery(new Term(
+ *         &quot;base&quot;, &quot;@:class=title&quot;)), true);
+ * </pre>
+ * 
+ * Negation enables searching for elements <em>without</em> some attribute(s).
+ * Example:
+ * 
+ * <pre>
+ * SpanAttributeQuery saq = new SpanAttributeQuery(new SpanTermQuery(new Term(
+ *         &quot;base&quot;, &quot;@:class=title&quot;)), true, true);
+ * </pre>
+ * 
+ * @author margaretha
  * */
-public class SpanAttributeQuery extends SimpleSpanQuery{
-	
-	boolean isNegation;
-	
-	public SpanAttributeQuery(SpanTermQuery firstClause, boolean collectPayloads) {
-		super(firstClause, collectPayloads);
-	}
-	
-	public SpanAttributeQuery(SpanTermQuery firstClause, boolean isNegation, 
-			boolean collectPayloads) {
-		super(firstClause, collectPayloads);
-		this.isNegation = isNegation;
-	}
+public class SpanAttributeQuery extends SimpleSpanQuery {
 
-	@Override
-	public SimpleSpanQuery clone() {
-		SpanAttributeQuery sq = new SpanAttributeQuery(
-				(SpanTermQuery) this.firstClause.clone(), 
-				this.isNegation,
-				this.collectPayloads);
-		sq.setBoost(getBoost());
-		return sq;
-	}
+    boolean negation;
 
-	@Override
-	public Spans getSpans(AtomicReaderContext context, Bits acceptDocs,
-			Map<Term, TermContext> termContexts) throws IOException {
-		return new AttributeSpans(this, context, acceptDocs, termContexts);
-	}
+    /**
+     * Constructs a SpanAttributeQuery based on the specified
+     * {@link SpanTermQuery} and set whether payloads are to be collected or
+     * not.
+     * 
+     * @param firstClause a {@link SpanTermQuery}
+     * @param collectPayloads a boolean flag representing the value
+     *        <code>true</code> if payloads are to be collected, otherwise
+     *        <code>false</code>.
+     */
+    public SpanAttributeQuery(SpanTermQuery firstClause, boolean collectPayloads) {
+        super(firstClause, collectPayloads);
+    }
 
-	@Override
-	public String toString(String field) {
-		StringBuilder sb = new StringBuilder();
-		sb.append("spanAttribute(");
-		sb.append(firstClause.toString(field));		
-		if (isNegation)
-			sb.append( ", not");		
-		sb.append(")");
-		sb.append(ToStringUtils.boost(getBoost()));
-		return sb.toString();
-	}
+    /**
+     * Constructs a SpanAttributeQuery based on the specified
+     * {@link SpanTermQuery}, which is also marked for negation/omission when
+     * matching to element/relation spans. Additionally set whether payloads are
+     * to be collected or not.
+     * 
+     * @param firstClause a {@link SpanQuery}
+     * @param negation a boolean flag representing the value <code>true</code>
+     *        if the attributes are to be omitted when matching with element or
+     *        relation spans, otherwise <code>false</code>.
+     * @param collectPayloads a boolean flag representing the value
+     *        <code>true</code> if payloads are to be collected, otherwise
+     *        <code>false</code>.
+     */
+    public SpanAttributeQuery(SpanTermQuery firstClause, boolean negation,
+            boolean collectPayloads) {
+        super(firstClause, collectPayloads);
+        this.negation = negation;
+    }
 
-	public boolean isNegation() {
-		return isNegation;
-	}
+    /** {@inheritDoc} */
+    @Override
+    public SimpleSpanQuery clone() {
+        SpanAttributeQuery sq = new SpanAttributeQuery(
+                (SpanTermQuery) this.firstClause.clone(), this.negation,
+                this.collectPayloads);
+        sq.setBoost(getBoost());
+        return sq;
+    }
 
-	public void setNegation(boolean isNegation) {
-		this.isNegation = isNegation;
-	}
+    @Override
+    public Spans getSpans(AtomicReaderContext context, Bits acceptDocs,
+            Map<Term, TermContext> termContexts) throws IOException {
+        return new AttributeSpans(this, context, acceptDocs, termContexts);
+    }
+
+    @Override
+    public String toString(String field) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("spanAttribute(");
+        sb.append(firstClause.toString(field));
+        if (negation)
+            sb.append(", not");
+        sb.append(")");
+        sb.append(ToStringUtils.boost(getBoost()));
+        return sb.toString();
+    }
+
+    /**
+     * Tells weather the attributes are to be omitted when matching to element
+     * or relation spans, or not.
+     * 
+     * @return <code>true</code> if the attributes are to be omitted when
+     *         matching to element or relation spans, <code>false</code>
+     *         otherwise.
+     */
+    public boolean isNegation() {
+        return negation;
+    }
+
+    /**
+     * Sets true if the attributes are to be omitted when matching to element or
+     * relation spans, false otherwise.
+     * 
+     * @param negation a boolean with value <code>true</code>, if the attributes
+     *        are to be omitted when matching to element or relation spans,
+     *        <code>false</code> otherwise.
+     */
+    public void setNegation(boolean negation) {
+        this.negation = negation;
+    }
 
 }