Armstrong, F.E. <br/><br/>
Tests for analysing the incombustible content of coal mine dust using instruments employing a gamma ray backscatter technique (BM-TPR 64) 
Armstrong, F.E. 
 - Washington  Bureau of mines  1973 
<br/><br/><label>Subjects--Topical Terms: </label><br/>POLVO EN LA MINA<br/>CONTROL DE POLVO EN LA MINA<br/>MINAS DE CARBON
<br/><br/><label>Universal Decimal Class. No.: </label>622.807