Buelletin:  International Statistical Institute Proceedings of the 43rd Session. 

 - Buenos Aires :   Instituto Nacional de Estadísticas y Censos,  1981. 
 - 3 v. : 
<br/><br/><label>ISBN: </label>9503200016 9503200024 
<br/><br/><label>Universal Decimal Class. No.: </label>519.22