Cell Ontology Variation Ontology Source
http://purl.obolibrary.org/obo/PR_000000001 http://purl.obolibrary.org/obo/VariO_0277 LOOM
http://purl.obolibrary.org/obo/SO_0000704 http://purl.obolibrary.org/obo/VariO_0272 LOOM
http://purl.obolibrary.org/obo/GO_1990904 http://purl.obolibrary.org/obo/VariO_0268 LOOM