Project(BGP( ?event <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://purl.org/NET/c4dm/event.owl#Event> .
             ?event <http://purl.org/NET/c4dm/event.owl#agent> ?person .
             ?person <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Person>),
        {?event, ?person})