Vanek, Jaroslav. <br/><br/>
The natural resource content of United States foreign trade, 1870-19 55 /    
Jaroslav Vanek. 
 - Cambridge, Ma. :   M.I.T Press,   1963. 
 - xvi, 142 p. :    ill. ;    24 cm. 
<br/><br/>Includes bibliographical references 
<br/><br/><label>Subjects--Geographic Terms: </label><br/> United States -- Commerce.