Critical materials. 

 - Washington :  Committee on interior and insular affairs,  1955. 
 - 619 p. ;  23 cm 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geología económica
<br/><br/><label>Index Terms--Genre/Form: </label><br/>Libro
<br/><br/><label>Universal Decimal Class. No.: </label>553(058)