Helth and safety in-house research development and demostration in fiscal year 1981 
U.S. Bureau of mines, Division of Minerals Health and Safety Technology 
 - Washington  Bureau of mines  1981 
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA<br/>RIESGOS
<br/><br/><label>Universal Decimal Class. No.: </label>622.8