diff --git a/rdf/tbox/filegraph/object-properties.owl b/rdf/tbox/filegraph/object-properties.owl
index ef8d47b6..0b9c619b 100644
--- a/rdf/tbox/filegraph/object-properties.owl
+++ b/rdf/tbox/filegraph/object-properties.owl
@@ -2068,8 +2068,9 @@ there is a measurement process p that has specified output m, a measurement datu
         <rdfs:range rdf:resource="http://www.w3.org/2006/vcard/ns#URL"/>
     </owl:ObjectProperty>
     
+<!-- VIVO modifications from first ISF release -->
 
-<!-- http://vivoweb.org/ontology/core#orcidId -->
+    <!-- http://vivoweb.org/ontology/core#orcidId -->
 
     <owl:ObjectProperty rdf:about="http://vivoweb.org/ontology/core#orcidId">
         <rdfs:label xml:lang="en">orcid id</rdfs:label>
@@ -2077,6 +2078,23 @@ there is a measurement process p that has specified output m, a measurement datu
     </owl:ObjectProperty>
 
 
+
+    <!-- http://vivoweb.org/ontology/core#roleContributesTo -->
+
+    <owl:ObjectProperty rdf:about="http://vivoweb.org/ontology/core#roleContributesTo">
+        <rdfs:label xml:lang="en-us">contributes to</rdfs:label>
+        <rdfs:domain rdf:resource="http://purl.obolibrary.org/obo/BFO_0000023"/>
+        <owl:inverseOf rdf:resource="http://vivoweb.org/ontology/core#contributingRole"/>
+    </owl:ObjectProperty>
+
+    <!-- http://vivoweb.org/ontology/core#contributingRole -->
+
+    <owl:ObjectProperty rdf:about="http://vivoweb.org/ontology/core#contributingRole">
+        <rdfs:label xml:lang="en-us">contributor</rdfs:label>
+        <rdfs:range rdf:resource="http://purl.obolibrary.org/obo/BFO_0000023"/>
+        <owl:inverseOf rdf:resource="http://vivoweb.org/ontology/core#roleContributesTo"/>
+    </owl:ObjectProperty> 
+
 <!-- Generated by the OWL API (version 3.3.1957) http://owlapi.sourceforge.net -->
 
 </rdf:RDF>