Georg eckert institute for international textbook research 

 - Braunschweig :  Internationale Schulbuchforschung,  1986. 
 - 30 p. ;  il. 
<br/><br/><label>ISBN: </label>3883044059 
<br/><br/><label>No. de Clasificación Universal Decimal: </label>OC 371.2 (100) =20 "1986" GEO