Kirk, E. (2010). Human footprint: Everything you will eat, use, wear, buy, and throw out in your lifetime. National Geographic.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Kirk, Ellen. Human Footprint: Everything You Will Eat, Use, Wear, Buy, and Throw Out in Your Lifetime. Washington, D.C.: National Geographic, 2010.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Kirk, Ellen. Human Footprint: Everything You Will Eat, Use, Wear, Buy, and Throw Out in Your Lifetime. National Geographic, 2010.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.