Crystal, D. (2004). The Penguin book of facts. New York: Penguin Books.
Chicago Style CitationCrystal, David. The Penguin Book of Facts. New York: Penguin Books, 2004.
Cita MLACrystal, David. The Penguin Book of Facts. New York: Penguin Books, 2004.
Atenció: Aquestes cites poden no estar 100% correctes.