TY  - BOOK
AU  - Verma, P. S.
AU  - Agarwal , V. K.
TI  - Environmental biology: Principles of ecology 
SN  - 8121908590
PY  - 1983///,2007
CY  - New Delhi
PB  - S Chand & Co.
KW  - Biology
KW  - Environment
ER  -