Asthana, D. K., & Asthana, M. (2006). Textbook of environmental studies. S Chand & Co Ltd.
Čikaški stil citiranjaAsthana, D. K., i Meera Asthana. Textbook of Environmental Studies. New Delhi: S Chand & Co Ltd, 2006.
MLA način citiranjaAsthana, D. K., i Meera Asthana. Textbook of Environmental Studies. S Chand & Co Ltd, 2006.
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