Question: Who was the coach of the team that won Superbowl XXX in 1996?
Answer(s):
answer: Barry Switzer

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ?c)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
?c ns:sports.sports_team.championships ns:m.076wz . 
?c ns:american_football.football_team.historical_coaching_staff ?y .
?y ns:american_football.football_historical_coach_position.coach ?x .
FILTER(NOT EXISTS {?y ns:american_football.football_historical_coach_position.from ?sk0} || 
EXISTS {?y ns:american_football.football_historical_coach_position.from ?sk1 . 
FILTER(xsd:datetime(?sk1) <= "1996-12-31"^^xsd:dateTime) })
FILTER(NOT EXISTS {?y ns:american_football.football_historical_coach_position.to ?sk2} || 
EXISTS {?y ns:american_football.football_historical_coach_position.to ?sk3 . 
FILTER(xsd:datetime(?sk3) >= "1996-01-01"^^xsd:dateTime) })
}