Question: Which rivers start in a country whose leader is Irene Mambilima?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?uri WHERE { ?x prop:leaderName <http://dbpedia.org/resource/Irene_Mambilima> . ?uri onto:sourceCountry ?x  . ?uri rdf:type onto:River}