APA استشهاد

Verma, P. S., & Agarwal, V. K. (2004). Environmental biology: Principles of ecology. S. Chand & Co.

استشهاد بنمط شيكاغو

Verma, P. S., و V. K. Agarwal. Environmental Biology: Principles of Ecology. New Delhi: S. Chand & Co, 2004.

MLA استشهاد

Verma, P. S., و V. K. Agarwal. Environmental Biology: Principles of Ecology. S. Chand & Co, 2004.