PREFIX foaf:    <http://xmlns.com/foaf/0.1/>
PREFIX vcard:   <http://www.w3.org/2001/vcard-rdf/3.0#>

CONSTRUCT { ?x foaf:firstName ?y .
			?x foaf:lastName ?z .
		  }

FROM <http://pagesperso-systeme.lip6.fr/Jean-Francois.Perrot/inalco/XML/RDF/Exemples/vcardCat.rdf>
WHERE
 {        ?x  vcard:N ?u .
          ?u vcard:Given ?y .
          ?u vcard:Family ?z.
 
 }