Roepke, Wallace W. <br/><br/>
Bit ignition potential with worn carbide tips (BM-TPR 121) 
Roepke, Wallace W. 
 - Washington  Bureau of mines  1983 
<br/><br/><label>Subjects--Topical Terms: </label><br/>TECNOLOGIA MINERA
<br/><br/><label>Universal Decimal Class. No.: </label>622.06