Question: What is the name of the wife of the author who wrote Winning the Future: A 21st Century Contract With America?
Answer(s):
answer: Callista Gingrich

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:book.author.book_editions_published ns:m.028yd0l . 
?c ns:people.person.spouse_s ?y .
?y ns:people.marriage.spouse ?x .
?x ns:people.person.gender ns:m.02zsn .
?y ns:people.marriage.from ?sk0 .
}
ORDER BY DESC(xsd:datetime(?sk0))
LIMIT 1