TY  - BOOK
AU  - Verma,P.S.
AU  - Agarwal,A.K.
TI  - Principles of ecology: Environmental biology
U1  - 574.5 
PY  - 1989///
CY  - New Delhi
PB  - S. Chand & Company Limited
KW  - Biology
KW  - Ecology
KW  - The ecosystem
KW  - Atmosphere and air
ER  -