diff --git a/public/ontology/diglib-struct.rdf b/public/ontology/diglib-struct.rdf
index 13f296ae04507701eb561faf1a8d1c76f137c94c..dfd982003ff0281d16125f7275a0b2986790f783 100644
--- a/public/ontology/diglib-struct.rdf
+++ b/public/ontology/diglib-struct.rdf
@@ -169,4 +169,7 @@
   <rdfs:Class rdf:about="http://uri.hab.de/ontology/diglib-struct#physSequence">
     <rdfs:label xml:lang="de">Seiten</rdfs:label>
   </rdfs:Class>
+  <rdfs:Class rdf:about="http://uri.hab.de/ontology/diglib-struct#Monograph">
+    <rdfs:label xml:lang="de">Werk</rdfs:label>
+  </rdfs:Class>
 </rdf:RDF>