assertion  retraction  graph  subject     predicate        object    datatype    annotation
1          0           graph  DOID:13160  rdfs:subClassOf  DOID:518  _IRI        
1          0           graph  DOID:518    oio:id           DOID:518  xsd:string  
1          0           graph  DOID:3445   rdfs:subClassOf  DOID:518  _IRI