diff --git a/ontology/graphofliberty.ttl b/ontology/graphofliberty.ttl
index c93122d..fcccc2c 100644
--- a/ontology/graphofliberty.ttl
+++ b/ontology/graphofliberty.ttl
@@ -233,7 +233,7 @@ rdac:C10004 rdf:type owl:NamedIndividual ,
                      :SearchableClass ;
             :associatedProperty <http://rdaregistry.info/Elements/a/datatype/P50291> ,
                                 <http://rdaregistry.info/Elements/a/datatype/P50292> ;
-            :categoryId "2"^^xsd:nonNegativeInteger .
+            :categoryId "3"^^xsd:nonNegativeInteger .
 
 
 ###  http://www.loc.gov/premis/rdf/v1#hasMessageDigest
@@ -284,11 +284,24 @@ rdfs:label rdf:type owl:NamedIndividual ;
            :indexedByField :Label .
 
 
+###  http://www.w3.org/2004/02/skos/core#Concept
+skos:Concept rdf:type owl:NamedIndividual ,
+                      :SearchableClass ;
+             :associatedProperty skos:definition ,
+                                 skos:prefLabel ;
+             :categoryId "2"^^xsd:nonNegativeInteger .
+
+
 ###  http://www.w3.org/2004/02/skos/core#definition
 skos:definition rdf:type owl:NamedIndividual ;
                 :indexedByField :Definition .
 
 
+###  http://www.w3.org/2004/02/skos/core#prefLabel
+skos:prefLabel rdf:type owl:NamedIndividual ;
+               :indexedByField :Label .
+
+
 ###  http://www.w3.org/ns/ldp#BasicContainer
 ldp:BasicContainer rdf:type owl:NamedIndividual ;
                    :readOnly "true"^^xsd:boolean .