Ager, D. V. (1963). Principles of paleoecology: An introduction to the study of how and where animals and plants lived in the past. Mc Graw-Hill.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Ager, Derek Victor. Principles of Paleoecology: An Introduction to the Study of How and Where Animals and Plants Lived in the Past. New York: Mc Graw-Hill, 1963.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Ager, Derek Victor. Principles of Paleoecology: An Introduction to the Study of How and Where Animals and Plants Lived in the Past. Mc Graw-Hill, 1963.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.