Question: Which organizations were founded in 1950?
SPARQL:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX onto: <http://dbpedia.org/ontology/>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT DISTINCT ?uri ?string
WHERE 
{
	?uri rdf:type onto:Organisation .
        ?uri prop:foundation ?date .
        FILTER regex(?date,'^1950') .
	OPTIONAL {?uri rdfs:label ?string . FILTER (lang(?string) = 'en') }
}