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#> PREFIX dct: <http://purl.org/dc/elements/1.1/> PREFIX dcc: <http://purl.org/dc/terms/> PREFIX calr: <http://www.w3.org/2002/12/cal#> SELECT distinct ?forum_name, ?post, ?url, ?summary, ?descr, ?location WHERE { ?forum rdf:type sioct:Calendar . ?forum sioc:id ?forum_name. ?forum sioc:container_of ?post . ?post rdf:type calr:vevent . OPTIONAL{?post dct:title ?title}. OPTIONAL{?post calr:url ?url }. OPTIONAL{?post calr:summary ?summary }. OPTIONAL{?post calr:description ?descr }. OPTIONAL{?post calr:dtstart ?start}. OPTIONAL{?post calr:location ?location}. }