SIOCRefPollsExample1 Data Space Post/Entry/Item Properties (sioc:Post predicates) * content * has_container * has_creator * id * link * topic (tags) PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX sioc: <http://rdfs.org/sioc/ns#> PREFIX sioct: <http://rdfs.org/sioc/types#> SELECT distinct ?attribute WHERE { ?forum a sioct:SurveyCollection. ?forum sioc:container_of ?post . ?post ?attribute ?o } ORDER BY ?attribute