Question: What drugs were in the music producer's system who produced "Whitney: The Greatest Hits" when she died?
Answer(s):
answer: Cocaine overdose

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.producer.releases_produced ns:m.0bflbsy . 
?c ns:people.deceased_person.cause_of_death ?x .
?x ns:people.cause_of_death.parent_cause_of_death ns:m.01tf_6 .
}