PREFIX sioc: <http://rdfs.org/sioc/ns#> PREFIX sioct: <http://rdfs.org/sioc/types#> PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT DISTINCT ?gender, ?fname, ?post WHERE { ?forum a sioct:Briefcase . ?forum sioc:container_of ?post. optional { ?post foaf:maker ?maker }. optional { ?maker foaf:gender ?gender } . optional { ?maker foaf:family_name ?fname } . }