- New Delhi :  Sterling [publishing private limited,  2001 
 - viii,  140p. : 
<br/><br/><label>ISBN: </label>8120722930 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Environment
<br/><br/><label>Dewey Class. No.: </label>333.7  / MUK P01E