Question: What is the name of the person the film The Unauthorized Biography of Johnny Cash's First Wife is about?
Answer(s):
answer: Vivian Liberto

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.film_subject.films ns:m.0vx85by . 
?c ns:people.person.spouse_s ?y .
?y ns:people.marriage.spouse ?x .
?y ns:people.marriage.type_of_union ns:m.04ztj .
?y ns:people.marriage.from ?sk0 .
}
ORDER BY xsd:datetime(?sk0)
LIMIT 1