ASK WHERE {
	<http://www.w3.org/2006/07/SWD/RDFa/testsuite/xhtml1-testcases/0033.xhtml> <http://purl.org/dc/elements/1.1/creator> ?a .
	?a <http://xmlns.com/foaf/0.1/name> "Ben Adida" .
	FILTER isBlank(?a)
}