Question: Give me all Canadian Grunge record labels.
SPARQL query:
PREFIX onto: <http://dbpedia.org/ontology/>
PREFIX res: <http://dbpedia.org/resource/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT DISTINCT ?uri ?string 
WHERE {
	?uri rdf:type onto:RecordLabel .
        ?uri onto:genre res:Grunge .
        ?uri onto:country res:Canada .
        OPTIONAL { ?uri rdfs:label ?string . FILTER (lang(?string) = 'en') } 
}