Rolston, Holmes. <br/><br/>
Environmental ethics :  duties to and values in the natural world. 

 - Philadelphia :  Temple University Press,  1988. 
<br/><br/>Includes bibliographical references. 
<br/><br/><label>ISBN: </label>087722501 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Human ecology -- Moral and ethical aspects.--Human ecology -- Moral and ethical aspects.