Question: Whose opponents are Ike Clanton and Billy Clanton?
SPARQL:
SELECT DISTINCT ?uri WHERE { ?uri <http://dbpedia.org/ontology/opponent> <http://dbpedia.org/resource/Ike_Clanton> . ?uri <http://dbpedia.org/ontology/opponent> <http://dbpedia.org/resource/Billy_Clanton> . }