Question: Which country with the calling code 855 was the Vietnam war located in?
Answer(s):
answer: Cambodia

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.07_nf)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.07_nf ns:time.event.locations ?x .
?x ns:location.country.calling_code "855" . 
}