PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://rdfs.org/sioc/ns#> PREFIX sioc: <http://rdfs.org/sioc/ns#> PREFIX foaf: <http://xmlns.com/foaf/0.1/> PREFIX dc: <http://purl.org/dc/elements/1.1/> SELECT ?project ?title ?id ?descr WHERE { ?usr rdf:type sioc:User. ?usr rdfs:account_of ?sr . optional {?sr foaf:project ?project}. optional {?project dc:title ?title}. optional {?project dc:identifier ?id}. optional {?project dc:description ?descr}. }