SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/sourcePlace> <http://dbpedia.org/resource/Richmond_Park> . ?x <http://dbpedia.org/property/mouthLocation> ?uri . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Stream>}
Where does the river end which starts in Richmond Park?
SELECT DISTINCT ?j WHERE { ?p property:mouth_location ?j . ?p rdf:type ontology:Stream . ?p property:source_place resource:Richmond_Park }
River Thames, Petersham, London
The mouth location of the stream whose source place is Richmond Park is [River Thames, Petersham, London].
The mouth of the river, the source of which is Richmond Park, is in [Thames, Hempham, London].