TY  - BOOK
AU  - Verma,P.S.
AU  - Agrawal,V.K.
TI  - Environmental biology (Priciples of ecology)
SN  - 8121908590
U1  - 628 
PY  - 2000///
CY  - New Delhi
PB  - S.Chand & Co. 
ER  -