Verma P.S. <br/><br/>
Environmental Biology 

 - Ist 
 - NEW DELHI  S. Chand & Company LTD.  1998 
 - 591p. 
<br/><br/><label>ISBN: </label>9788121908597 
<br/><br/><label>Dewey Class. No.: </label>577  / VER-ENV