What river ends in Indian Ocean and also starts somewhere in Zambia?
SELECT DISTINCT ?uri WHERE {?uri <http://dbpedia.org/ontology/riverMouth> <http://dbpedia.org/resource/Indian_Ocean> . ?uri <http://dbpedia.org/ontology/sourceCountry> <http://dbpedia.org/resource/Zambia>  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/River>}
Indian_Ocean Zambia