National Geographic Society (U.S.), National Geographic Channel (Television station : Washington, D.C.), Warner Home Video (Firm), Maltby, C., & Vargas, E. (2008). Human footprint (Widescreen version.). Distributed by Warner Home Video.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNational Geographic Society (U.S.), D.C.) National Geographic Channel (Television station : Washington, Warner Home Video (Firm), Clive Maltby, और Elizabeth Vargas. Human Footprint. Widescreen version. [Burbank, Calif.]: Distributed by Warner Home Video, 2008.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNational Geographic Society (U.S.), et al. Human Footprint. Widescreen version. Distributed by Warner Home Video, 2008.
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