Question: Which country has outflow of  Lake Uniamsi and  inflows of the Cahora Bassa?
SPARQL query:
PREFIX res: <http://dbpedia.org/resource/>
PREFIX prop: <http://dbpedia.org/property/>
 SELECT DISTINCT ?uri WHERE { res:Lake_Uniamési prop:outflow ?uri. res:Cahora_Bassa prop:inflow ?uri}