Crockett, R. N. <br/><br/>
International strategic minerals inventory summary report :  niobium (columbium) and tantalum / 
by R. N. Crockett and David M. Sutphin 
 - Washington :  U.S. Government Printing Office,  1993 
 - vi, 36 p. :  ill., maps ;  27 cm. 
 - U.S. Geological Survey circular ;  930-M .
<br/><br/> Prepared as a cooperative effort among earth-science and mineral-resource agencies of Australia, Canada, the Federal Republic of Germany, the Republic of South Africa, the United Kingdom, and the United States of America 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Niobium ores<br/>Tantalum ores<br/>Strategic materials
<br/><br/><label>Dewey Class. No.: </label>333.85465