Relations Ontology UMLS Semantic Network Source
http://purl.obolibrary.org/obo/GO_0007610 http://purl.bioontology.org/ontology/STY/T053 LOOM
http://purl.obolibrary.org/obo/GO_0003674 http://purl.bioontology.org/ontology/STY/T044 LOOM
http://purl.obolibrary.org/obo/CL_0000000 http://purl.bioontology.org/ontology/STY/T025 LOOM