diff --git a/src/cco-modules/ExtendedRelationOntology.ttl b/src/cco-modules/ExtendedRelationOntology.ttl
index ff68aa6..503f769 100644
--- a/src/cco-modules/ExtendedRelationOntology.ttl
+++ b/src/cco-modules/ExtendedRelationOntology.ttl
@@ -1,5 +1,4 @@
 @prefix : <https://www.commoncoreontologies.org/ExtendedRelationOntology#> .
-@prefix cco: <http://www.ontologyrepository.com/CommonCoreOntologies/> .
 @prefix obo: <http://purl.obolibrary.org/obo/> .
 @prefix owl: <http://www.w3.org/2002/07/owl#> .
 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
diff --git a/src/cco-modules/QualityOntology.ttl b/src/cco-modules/QualityOntology.ttl
index 861bcf6..ead7e48 100644
--- a/src/cco-modules/QualityOntology.ttl
+++ b/src/cco-modules/QualityOntology.ttl
@@ -1,5 +1,4 @@
 @prefix : <https://www.commoncoreontologies.org/QualityOntology/> .
-@prefix cco: <https://www.commoncoreontologies.org/> .
 @prefix obo: <http://purl.obolibrary.org/obo/> .
 @prefix owl: <http://www.w3.org/2002/07/owl#> .
 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .