International yearbook of education, Vol. XXV, 1963. 

 - Geneva :  Paris :  IBE,  UNESCO,  1963. 
 - 487 p. 
 - IBE publication ;  262. .
<br/><br/><label>No. de Clasificación Universal Decimal: </label>OC 37 (100) =20 "1963" INN No.25.