Question: Which Pink Floyd vocalists have died from cancer?
Answer(s):
answer: Syd Barrett
answer: Richard Wright

SPARQL query:
#MANUAL SPARQL
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
  {
    ns:m.01wv9xn ns:music.musical_group.member ?y .
    ?y ns:music.group_membership.member ?x ;
       ns:music.group_membership.role ns:m.0290ngj . #vocals
  }
  UNION
  {
    ns:m.01wv9xn ns:music.musical_group.member ?y .
    ?y ns:music.group_membership.member ?x ;
       ns:music.group_membership.role ns:m.0_sv_90 . #lead vocals
  }?x ns:people.deceased_person.cause_of_death ns:m.0qcr0 . 
}