Stahl, Robert Lee <br/><br/>
Guide to geologic features affecting coal mine roof 
Stahl, Robert Lee 
 - Washington  Department of Labor  1979 
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA<br/>CARACTERISTICAS GEOLOGICAS
<br/><br/><label>Universal Decimal Class. No.: </label>622.03