Question: List the spouses of the stars of Judy Collins and Elizabeth Cotten: Rainbow Quest.?
Answer(s):
answer: Peter Taylor
answer: Louis Nelson

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.film ns:m.0cs00nz . 
?c ns:people.person.spouse_s ?y .
?y ns:people.marriage.spouse ?x .
?y ns:people.marriage.type_of_union ns:m.04ztj .
}