Question: What is the former team of the american football players whose position is Running back?
SPARQL:
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/position> <http://dbpedia.org/resource/Running_back> . ?x <http://dbpedia.org/ontology/formerTeam> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/AmericanFootballPlayer>}