APA استشهاد

Asthana, D. K., & Asthana, M. (2006). Textbook of environmental studies. S Chand & Co Ltd.

استشهاد بنمط شيكاغو

Asthana, D. K., و Meera Asthana. Textbook of Environmental Studies. New Delhi: S Chand & Co Ltd, 2006.

MLA استشهاد

Asthana, D. K., و Meera Asthana. Textbook of Environmental Studies. S Chand & Co Ltd, 2006.