"RDF Primer" . _:vb50819239 "Eric Miller" . . "2004-02-10" . . _:vb50819238 . _:vb50819239 . . _:vb50819238 "Frank Manola" . _:vb50819240 . _:vb50819240 . _:vb50819239 . _:vb50819240 . _:vb50819238 . . . .