Chitkara, M. G. <br/><br/>
Encyclopaedia of ecology, environment and pollution 
M. G. Chitkara 
 - New Delhi  APH  1998 
 - 15v. 
<br/><br/><label>ISBN: </label>8170248817 
<br/><br/><label>Dewey Class. No.: </label>577.270354 C448E