Who speaks for earth? / 
Barbara Ward ... [et al.]. 
 - New York :  Norton,  1973 
 - 173 p. ;  21 cm. 
<br/><br/><label>ISBN: </label>0393063925 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Human ecology.<br/>Population.<br/>Pollution.