Question: What are the source of the streams whose one of the source is Calera, Oklahoma?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?uri WHERE { ?x onto:source <http://dbpedia.org/resource/Calera,_Oklahoma> . ?x onto:source ?uri  . ?x rdf:type onto:Stream}