Question: Where is the headquarters of the public transit system which operators Go-to-card ?
SPARQL:
SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Go-To_card> <http://dbpedia.org/property/operator> ?x . ?x <http://dbpedia.org/property/headquarters> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/PublicTransitSystem>}