Guzzardi, Walter. <br/><br/>
Horizonte Usa ;   No. 18 

 - Washington-XXU :   U.S. Information Agency,   1976. 
 - p. 61-64 
 - Bimestral 
 - No. 18(1976) 
 - Horizonte Usa ;   No. 18 .
 - U.S. Information Agency. .