Dunlop, J.P. <br/><br/>
The production of metals and metallic ores in 1912 and 1913. 

 - Washington, D.C.  Government Printing Office  1914 
 - pp. 747-753 
<br/><br/> Impreso 
<br/><br/><br/>Ingles 
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA