select ?dd, ?mb 
 from 
 file:rdf/000068.rdf 
 where
 (dc::description http://example.com/photos/1.jpg ?dd) 
 (foaf::depiction ?per http://example.com/photos/1.jpg) 
 (foaf::mbox ?per ?mb) 
 using dc for http://purl.org/dc/elements/1.1/ 
 foaf for http://xmlns.com/foaf/0.1/ 
 rdf for http://www.w3.org/1999/02/22-rdf-syntax-ns#