APA aipamena

Hoffer, W., & Hoffer, M. M. (1989). Freefall. St. Martin's Press.

Chicago Style aipamena

Hoffer, William, and Marilyn Mona Hoffer. Freefall. New York: St. Martin's Press, 1989.

MLA aipamena

Hoffer, William, and Marilyn Mona Hoffer. Freefall. St. Martin's Press, 1989.