Krauss, Melvyn B.. <br/><br/>
Geometric Approach to International Trade /  

 - 1st ed /  
 - Oxford :   Basil Blackwell ,   1990 
 - p.96 :  
<br/><br/><label>ISBN: </label>0-631-18470-8 
<br/><br/><label>Dewey Class. No.: </label>X:54:(B6)  / L9;1