PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX sioc: <http://rdfs.org/sioc/ns#> PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT DISTINCT ?forum_name, ?title, ?post as ?url, ?content WHERE { ?forum rdf:type "Tutorial". ?forum sioc:description ?forum_name. ?forum sioc:container_of ?post. ?post rdf:type foaf:Document. OPTIONAL { ?post dc:title ?title } . OPTIONAL { ?post sioc:content ?content } . } LIMIT 10