rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
rdfs="http://www.w3.org/2000/01/rdf-schema#"
owl="http://www.w3.org/2002/07/owl#"
xsd="http://www.w3.org/2001/XMLSchema#"
foaf="http://xmlns.com/foaf/0.1/"
dc="http://purl.org/dc/elements/1.1/"
