Verma, P. S. (1983). Environmental Biology: Principles of Ecology (1st. ed.). S. Chand & Company Ltd..
Chicago-čujuhus (17. p.)Verma, P. S. Environmental Biology: Principles of Ecology. 1st. ed. New Delhi: S. Chand & Company Ltd., 1983.
MLA-čujuhus (9. p.)Verma, P. S. Environmental Biology: Principles of Ecology. 1st. ed. S. Chand & Company Ltd., 1983.
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