Tryon, F. G. <br/><br/>
Technology and the mineral industries. 

 - Philadelphia :  National Resources Committee,  1937. 
 - 63 p. :  il. ;  25 cm 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Minería<br/>Industria minera
<br/><br/><label>Index Terms--Genre/Form: </label><br/>Libro
<br/><br/><label>Universal Decimal Class. No.: </label>622.1