TY  - BOOK
AU  - Asthana D.K. and Asthana Meera
TI  - A textbook of environmental studies / 
SN  - 8121927641
U1  - 333.707 ASTA 
PY  - 2006///
CY  - New Delhi
PB  - S. Chand & Company Ltd.
KW  - Environmental studies
ER  -