Question: Who was the coach of the Minnesota Vikings that retired in 1951?
Answer(s):
answer: Bud Grant

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.051q5)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.051q5 ns:american_football.football_team.historical_coaching_staff ?y .
?y ns:american_football.football_historical_coach_position.coach ?x .
?x ns:sports.pro_athlete.career_end "1951"^^xsd:dateTime . 
}