Johnson, C. (2007). The practical zone system : for film and digital photography: A simple guide to photographic control (4th ed.). Elsevier/Focal Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रJohnson, Chris. The Practical Zone System : For Film and Digital Photography: A Simple Guide to Photographic Control. 4th ed. Boston: Elsevier/Focal Press, 2007.
एमएलए (9वां संस्करण) प्रशस्ति पत्रJohnson, Chris. The Practical Zone System : For Film and Digital Photography: A Simple Guide to Photographic Control. 4th ed. Elsevier/Focal Press, 2007.
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