Savinder Singh <br/><br/>
Paryavaran bhoogol 

 - 2nd ed. 
 - Allahabad  Prayag Pustak Bhawan  1996 
 - viii, 516 p. 
<br/><br/><label>ISBN: </label> RS450 
<br/><br/><label>Dewey Class. No.: </label>910.13637 S94P