Cita APA (7th ed.)

Johnson, C. (1986). The practical zone system: A simple guide to photographic control. Focal Press.

Cita Chicago (17th ed.)

Johnson, Chris. The Practical Zone System: A Simple Guide to Photographic Control. Boston: Focal Press, 1986.

Cita MLA (9th ed.)

Johnson, Chris. The Practical Zone System: A Simple Guide to Photographic Control. Focal Press, 1986.