Question: What are the names of the parents of the person who said "But thy eternal summer shall not fade."?
Answer(s):
answer: John Shakespeare
answer: Mary Shakespeare

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:people.person.quotations ns:m.048ddn7 . 
?c ns:people.person.parents ?x .
}