Cita APA (7th ed.)

Sagan, C., & Leonard, J. N. 1. j. a. (1972). Planets. Time-Life Books.

Cita Chicago (17th ed.)

Sagan, Carl, i Jonathan Norton 1903- joint auth Leonard. Planets. New York: Time-Life Books, 1972.

Cita MLA (9th ed.)

Sagan, Carl, i Jonathan Norton 1903- joint auth Leonard. Planets. Time-Life Books, 1972.