assertion  retraction  graph  subject       predicate        object     datatype    annotation
1          0           graph  DOID:5519     rdfs:subClassOf  DOID:1520  _IRI        
1          0           graph  DOID:0080183  rdfs:subClassOf  DOID:1520  _IRI        
1          0           graph  DOID:1520     oio:id           DOID:1520  xsd:string  
1          0           graph  DOID:234      rdfs:subClassOf  DOID:1520  _IRI