diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/er/relation/RelationManagement.java b/src/main/java/org/gcube/informationsystem/resourceregistry/er/relation/RelationManagement.java
index 3ba7f38..a0aab8c 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/er/relation/RelationManagement.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/er/relation/RelationManagement.java
@@ -101,12 +101,18 @@ public abstract class RelationManagement<R extends Relation> extends
 	public JSONObject serializeAsJson() throws ResourceRegistryException {
 		JSONObject relation = serializeSelfOnly();
 
-		Vertex target = element.getVertex(Direction.IN);
 		try {
-			EntityManagement entityManagement = EntityManagement
+			Vertex source = element.getVertex(Direction.OUT);
+			EntityManagement sourceEntityManagement = EntityManagement
+					.getEntityManagement(orientGraph, source);
+			relation.put(Relation.SOURCE_PROPERTY, sourceEntityManagement.serializeSelfOnly());
+			
+			Vertex target = element.getVertex(Direction.IN);
+			EntityManagement targetEntityManagement = EntityManagement
 					.getEntityManagement(orientGraph, target);
 			relation.put(Relation.TARGET_PROPERTY,
-					entityManagement.serializeAsJson());
+					targetEntityManagement.serializeAsJson());
+			
 		} catch (ResourceRegistryException e) {
 			logger.error("Unable to correctly serialize {}. This is really strange and should not occur.", element, e);
 			throw e;