Question: Where was the Vietnam War located where CO2 emissions per capita was once 1960 metric tons?
Answer(s):
answer: Vietnam
answer: Cambodia
answer: Cambodia
answer: Laos
answer: Laos

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.statistical_region.co2_emissions_per_capita ?c .
?c ns:measurement_unit.dated_metric_ton.date "1960"^^xsd:dateTime . 
}