Question: Which character is played in Seinfeld by the actor who once played the character of Boris Yellnikoff?
Answer(s):
answer: George Steinbrenner

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:film.actor.film ?k .
?k ns:film.performance.character ns:m.05yrt1c . 
?c ns:tv.tv_actor.starring_roles ?y .
?y ns:tv.regular_tv_appearance.character ?x .
?y ns:tv.regular_tv_appearance.series ns:m.072kp .
}