Question: Who are the producers of the movies  which has music by Gary Chang ?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?uri WHERE { ?x prop:music <http://dbpedia.org/resource/Gary_Chang> . ?x prop:producer ?uri . ?x rdf:type onto:Film}