Question: What country that exports to Vietnam contains the Mekong River?
Answer(s):
answer: Laos

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.0j0g5)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.0j0g5 ns:location.location.partially_containedby ?x .
?x ns:location.statistical_region.places_exported_to ?c .
?c ns:location.imports_and_exports.exported_to ns:m.01crd5 . 
}