Richardson, Paul A. <br/><br/>
Active list of permissible explosives and blasting devices approvinciaed before July 1, 1970  
Richardson, Paul A. 
 - Washington  Bureau of mines  1970 
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA<br/>EXPLOSIVOS
<br/><br/><label>Universal Decimal Class. No.: </label>622.235.2