Question: How many artists' works are in Muse d'Orsay?
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 COUNT(?uri) WHERE { ?x prop:museum <http://dbpedia.org/resource/Musée_d'Orsay> . ?x prop:artist ?uri . ?uri rdf:type onto:Artist}