Question: Which river's source mountain is Baikal Mountains and it's mouth is Lena Delta Wildlife Reserve?
SPARQL query: SELECT DISTINCT ?uri WHERE {?uri <http://dbpedia.org/ontology/sourceMountain> <http://dbpedia.org/resource/Baikal_Mountains> . ?uri <http://dbpedia.org/ontology/riverMouth> <http://dbpedia.org/resource/Lena_Delta_Wildlife_Reserve>  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/River>}
Answer: [Lena River] is the river whose source mountain is Baikal Mountains and mouth is Lena Delta Wildlife Reserve.