diff --git a/src/main/java/org/gcube/resourcemanagement/model/impl/entities/facets/ProvenanceFacetImpl.java b/src/main/java/org/gcube/resourcemanagement/model/impl/entities/facets/ProvenanceFacetImpl.java
index 1fae72f..e165c7f 100644
--- a/src/main/java/org/gcube/resourcemanagement/model/impl/entities/facets/ProvenanceFacetImpl.java
+++ b/src/main/java/org/gcube/resourcemanagement/model/impl/entities/facets/ProvenanceFacetImpl.java
@@ -3,8 +3,6 @@
  */
 package org.gcube.resourcemanagement.model.impl.entities.facets;
 
-import java.util.UUID;
-
 import org.gcube.com.fasterxml.jackson.annotation.JsonTypeName;
 import org.gcube.informationsystem.model.impl.entities.FacetImpl;
 import org.gcube.resourcemanagement.model.reference.entities.facets.ProvenanceFacet;
@@ -22,7 +20,7 @@ public class ProvenanceFacetImpl extends FacetImpl implements ProvenanceFacet {
 	private static final long serialVersionUID = 1014553736569877775L;
 	
 	protected Relationship relationship;
-	protected UUID reference;
+	protected String reference;
 	protected ValueSchema document;	
 	
 	/**
@@ -41,6 +39,21 @@ public class ProvenanceFacetImpl extends FacetImpl implements ProvenanceFacet {
 		this.relationship = relationship;
 	}
 	
+	/**
+	 * @return the reference
+	 */
+	@Override
+	public String getReference() {
+		return reference;
+	}
+	
+	/**
+	 * @param reference the reference to set
+	 */
+	@Override
+	public void setReference(String reference) {
+		this.reference = reference;
+	}
 	/**
 	 * @return the document
 	 */
diff --git a/src/main/java/org/gcube/resourcemanagement/model/reference/entities/facets/ProvenanceFacet.java b/src/main/java/org/gcube/resourcemanagement/model/reference/entities/facets/ProvenanceFacet.java
index f930e7f..76ad884 100644
--- a/src/main/java/org/gcube/resourcemanagement/model/reference/entities/facets/ProvenanceFacet.java
+++ b/src/main/java/org/gcube/resourcemanagement/model/reference/entities/facets/ProvenanceFacet.java
@@ -41,6 +41,11 @@ public interface ProvenanceFacet extends Facet {
 	
 	public void setRelationship(Relationship relationship);
 	
+	@ISProperty(description = "The ID of the referenced resource.")
+	public String getReference();
+	
+	public void setReference(String reference);
+	
 	@ISProperty(description = "Provenance Document, e.g., an XML according to the reference schema.")
 	public ValueSchema getDocument();