Barger, Harold and Schurr, S. H. <br/><br/>
Mining industries, 1899, 1939; a study of output employment and productivity   

 - New York  NBER  1944 
 - xxii, 452p. 
<br/><br/>  
<br/><br/><label>Dewey Class. No.: </label>338.20973  / B251.MI