Disabled pid for resource in the results.

Change-Id: I997dbb2853a5e22f0a91df0c853d0a0288b1177f
diff --git a/ChangeLog b/ChangeLog
index 0255f82..c0e1279 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,7 +6,7 @@
 - Implemented search for protected resources by using public metadata search 
   web-service and adding Diagnostics. (#64)
 - Added support for match-id with signatures. 
-- 
+- Add resource reference.
 
 1.0.7-SNAPSHOT
 
diff --git a/src/main/java/de/ids_mannheim/korap/sru/KorapSRUSearchResultSet.java b/src/main/java/de/ids_mannheim/korap/sru/KorapSRUSearchResultSet.java
index b950aa4..b4406d9 100644
--- a/src/main/java/de/ids_mannheim/korap/sru/KorapSRUSearchResultSet.java
+++ b/src/main/java/de/ids_mannheim/korap/sru/KorapSRUSearchResultSet.java
@@ -115,7 +115,7 @@
     public void writeRecord(XMLStreamWriter writer) throws XMLStreamException {
         KorapMatch match = korapResult.getMatch(i);
         match.parseMatchId();
-        XMLStreamWriterHelper.writeStartResource(writer, match.getMatchId(),
+        XMLStreamWriterHelper.writeStartResource(writer, null,
                 reference);
         XMLStreamWriterHelper.writeStartResourceFragment(writer, null, null);