Ackermann, A.S.E. <br/><br/>
Coal-cutting by machinery in America 

 - London  The Colliery Guardian Company, Ltd.  1902 
 - 134 p.  láms. 
 - Colliery Guardian Series of Handbooks  n.16 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>ARRANQUE<br/>CARBON<br/>MINERIA DEL CARBON
<br/><br/><label>Universal Decimal Class. No.: </label>A/622.33/A17