Johnston, R. J. (Ronald John) <br/><br/>
The world trade system  some enquiries into its spatial structure 
R. J. Johnston 
 - St. Martin's Press : New York  1976 
 - xvi, 208 p. ; 22 cm. 
<br/><br/>Includes bibliographical references and index. 
<br/><br/><label>LCCN: </label>76-006744 //r84 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Commerce--Mathematical models