Thinking at crossroads: In search of new languages / 
Eduardo Portella. 
 - Paris :  UNESCO,  2002. 
 - 286 p. 
 - The Philosopher's library .
<br/><br/><label>ISBN: </label>9231037258 
<br/><br/><label>No. de Clasificación Universal Decimal: </label>1 =20 "2002" CAM.