What is the river whose source is Cowombat Flat and has it's mouth located in Murray Mouth?
SELECT DISTINCT ?uri WHERE {?uri <http://dbpedia.org/ontology/source> <http://dbpedia.org/resource/Cowombat_Flat> . ?uri <http://dbpedia.org/ontology/riverMouth> <http://dbpedia.org/resource/Murray_Mouth>  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/River>}
Cowombat_Flat Murray_Mouth