Question: Of the times that the Dallas cowboys won the Superbowl, which ended before January 15,1978?
Answer(s):
answer: Super Bowl VI

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.02896)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.02896 ns:sports.sports_team.championships ?x .
?x ns:time.event.end_date ?num .
FILTER (?num < "1978-01-15"^^xsd:dateTime) . 
}