Question: Who developed Quake engine?
SPARQL query:
PREFIX onto: <http://dbpedia.org/ontology/> PREFIX res: <http://dbpedia.org/resource/> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> SELECT DISTINCT ?uri ?string WHERE { res:Quake_engine onto:developer ?uri OPTIONAL { ?uri rdfs:label ?string FILTER ( lang(?string) = "en" ) } }