Verma. P.S. <br/><br/>
Environmental biology (Principles of  ecology) 
by P. S. Verma and V. K. Agrawal 
 - New Delhi  S Chand and Company  2000 
 - 591p. 
<br/><br/><label>ISBN: </label>81 219 0859 0 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Biology<br/>Ecology
<br/><br/><label>Dewey Class. No.: </label>574.5  / VER/E