Question: Find the artist who recorde Oklahoma Swing, what is the name of this person's son?
Answer(s):
answer: Shelby Blackstock

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:music.featured_artist.recordings ns:m.0mk8k4 . 
?c ns:people.person.children ?x .
?x ns:people.person.gender ns:m.05zppz .
}