Spencer, Ellsworth R. <br/><br/>
Lightweight fiberglass feed leg for hand held pneumatic percussion rock drills 
Spencer, Ellsworth R. 
 - Washington  Bureau of mines  1985 
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA<br/>HERRAMIENTAS DE PERFORACION
<br/><br/><label>Universal Decimal Class. No.: </label>622.24.05