Quién defiende la tierra? 
Barbara Ward [y otros]; compilación de Maurice Strong; traducción de Juan José Utrilla. 
 - México  Fondo de Cultura Económica  c1975. 
 - 156 p. 
<br/><br/> Translation of : Who speaks for earth. 
<br/><br/><label>LCCN: </label>72011726  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Human ecology--Addresses, essays, lectures.<br/>Pollution--Addresses, essays, lectures.<br/>Population--Addresses, essays, lectures.
<br/><br/><label>Dewey Class. No.: </label>301.31