Question: What books were written by the person who said, "Friendship is essentially a partnership:?
Answer(s):
answer: Nicomachean ethics
answer: Nicomachean ethics.
answer: The Nicomachean ethics
answer: Nicomachean ethics
answer: Nicomachean ethics
answer: Nicomachean ethics
answer: The Nicomachean ethics
answer: The Nicomachean ethics
answer: The Nicomachean Ethics
answer: The Nicomachean Ethics
answer: Nicomachean Ethics
answer: Nicomachean Ethics
answer: The Nicomachean Ethics
answer: Nicomachean ethics
answer: Nicomachean ethics.
answer: The Nicomachean ethics
answer: The Nicomachean ethics
answer: Nicomachean ethics
answer: The Nicomachean ethics
answer: Nicomachean ethics
answer: The Nicomachean ethics
answer: Nicomachean ethics
answer: Nicomachean ethics
answer: Nicomachean ethics
answer: The Nicomachean Ethics (Penguin Classics)
answer: Nicomachean Ethics (Large Print)
answer: Nicomachean Ethics (Loeb Classical Library®)
answer: The Nicomachean Ethics (Great Books in Philosophy)
answer: The Nicomachean Ethics (Wordsworth Classics) (Wordsworth Classics)

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.048ffjq . 
?c ns:book.author.book_editions_published ?x .
}