Injury experience in coal mining, 1977 
U.S. Bureau of mines.Division of Mining Information Systems Health and Safety Analysis Center 
 - Washington  Department of labor  1979 
<br/><br/><label>Subjects--Topical Terms: </label><br/>LESIONES EN LA MINA<br/>MINAS DE CARBON
<br/><br/><label>Universal Decimal Class. No.: </label>622.861