@prefix dcterms: <http://purl.org/dc/terms/> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

foaf:birthday a owl:DatatypeProperty ;
    rdfs:label "has birthday"@en ;
    rdfs:comment "The date of birth of an agent."@en ;
    rdfs:isDefinedBy foaf: ;
    rdfs:range xsd:date ;
    rdfs:subPropertyOf dcterms:date .