Heger, E.A <br/><br/>
Developments in commercial education / 
E.A. Heger. 
 - Paris :  UNESCO,  1984. 
 - 94 p. 
 - Studies in technical and vocational education ;  1. .
<br/><br/><label>No. de Clasificación Universal Decimal: </label>373.61 (100) =20 1984HEG No.1.