added ExternalReference to PlanForILAP

@@ -2074,6 +2074,12 @@ NOTE 2  A Plan for Activity can define a number of part activities which are rel
     ] ;
   rdfs:subClassOf [
       rdf:type owl:Restriction ;
+      owl:minQualifiedCardinality "0"^^xsd:nonNegativeInteger ;
+      owl:onClass :ExternalReference ;
+      owl:onProperty :hasExternalReference ;
+    ] ;
+  rdfs:subClassOf [
+      rdf:type owl:Restriction ;
       :shouldBeInternalAndExternalRef "true"^^xsd:boolean ;
       owl:minQualifiedCardinality "0"^^xsd:nonNegativeInteger ;
       owl:onClass :PlanForILAP ;