Dyfyniad APA

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

Dyfyniad Arddull Chicago

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

Dyfyniad MLA

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

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