APA استشهاد

Sagan, C., & Leonard, J. N. (1967). <Planets>. Time life books.

استشهاد بنمط شيكاغو

Sagan, Carl, و Jonathan Norton Leonard. <Planets>. New York: Time life books, 1967.

MLA استشهاد

Sagan, Carl, و Jonathan Norton Leonard. <Planets>. Time life books, 1967.