Question: Where does the river flows into, which starts in Gredelj?
SPARQL query: SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/source> <http://dbpedia.org/resource/Gredelj> . ?x <http://dbpedia.org/ontology/riverMouth> ?uri  . }
Answer: The mouth of the river whose source is in Gredelj is [Adriatic Sea].