Question: Is Olyokma River the right tributary of Lena River?
SPARQL query: ASK WHERE { <http://dbpedia.org/resource/Lena_River> <http://dbpedia.org/ontology/rightTributary> <http://dbpedia.org/resource/Olyokma_River> }
Answer: [Yes], Olyokma River is the right tributary of Lena River.