CBSE UGC-NET Environmental Science (Paper ii & iii)/ 
Singh, B.B. 
 - New Delhi:  Ramesh,  2015. 
 - 640 p. 
<br/><br/><label>ISBN: </label>9788178127224 
<br/><br/><label>Dewey Class. No.: </label>363   / SIN/C