Which labels signs up progressive rock bands?
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/property/genre> <http://dbpedia.org/resource/Progressive_rock> . ?x <http://dbpedia.org/ontology/recordLabel> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/MusicalArtist>}
Progressive_rock