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.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)National Geographic Society (U.S.), D.C.) National Geographic Channel (Television station : Washington, Warner Home Video (Firm), Clive Maltby, و Elizabeth Vargas. Human Footprint. Widescreen version. [Burbank, Calif.]: Distributed by Warner Home Video, 2008.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)National Geographic Society (U.S.), et al. Human Footprint. Widescreen version. Distributed by Warner Home Video, 2008.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.