refer https://w3id.org/framester/pb/pbdata/refer.02 <https://w3id.org/framester/pb/pbschema/RoleSet> rdfs:label xsd:string refer rdf:type <https://w3id.org/framester/pb/pbschema/RoleSet> <https://w3id.org/framester/pb/pbschema/hasRole> <https://w3id.org/framester/pb/pbdata/refer.02__0> <https://w3id.org/framester/pb/pbdata/refer.02__1> <https://w3id.org/framester/pb/pbdata/refer.02__2> risorse dalla linked data cloud