diff --git a/oaipmh-core/src/main/java/info/textgrid/middleware/SetListDeliverer.java b/oaipmh-core/src/main/java/info/textgrid/middleware/SetListDeliverer.java
index c9a596212480d112f9f00415e9aaf4d45f6b6770..87311c3ca5798132c5c8113b76f73ca53b1ba9c1 100644
--- a/oaipmh-core/src/main/java/info/textgrid/middleware/SetListDeliverer.java
+++ b/oaipmh-core/src/main/java/info/textgrid/middleware/SetListDeliverer.java
@@ -150,7 +150,7 @@ public class SetListDeliverer {
       log.info("collectionFilterTerm metadasta entryset: "
           + collectionFilterTerm.getMetaData().entrySet());
 
-      collectionFilter.subAggregation(OLDcollectionFilterTerm);
+      OLDcollectionFilter.subAggregation(OLDcollectionFilterTerm);
       searchSourceBuilder.aggregation(OLDcollectionFilter);
     }