SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/source> <http://dbpedia.org/resource/Gredelj> . ?x <http://dbpedia.org/ontology/riverMouth> ?uri . }
Where does the river flows into, which starts in Gredelj?
SELECT DISTINCT ?q WHERE { ?z property:river_mouth ?q . . ?z property:source resource:Gredelj }
Adriatic Sea
The mouth of the river whose source is in Gredelj is [Adriatic Sea].
The river which starts in Gredelj has river mouth [Adriatic Sea].
The mouth of the rive with source having Gredelj is [Adriatic Sea].
The mouth of the river that has Gredel has source is [Adriatic Sea].