Sagan, C. (1985). Cosmos. Ballantine Books.
Cita Chicago (17th ed.)Sagan, Carl. Cosmos. New York: Ballantine Books, 1985.
Cita MLA (8th ed.)Sagan, Carl. Cosmos. Ballantine Books, 1985.
Atenció: Aquestes cites poden no estar 100% correctes.
Cita APA (7th ed.)