Question: Which river's source country is Zambia and mouth country is Mozambique?
SPARQL:
SELECT DISTINCT ?uri WHERE {?uri <http://dbpedia.org/ontology/sourceCountry> <http://dbpedia.org/resource/Zambia> . ?uri <http://dbpedia.org/property/mouthCountry> <http://dbpedia.org/resource/Mozambique>  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/River>}