Hours and earnings in anthracite and bituminous coal mining. 

 - Washington,  Govt. print. off.,  1922. 
 - iv, 63 p.  incl. tables.  23 cm. 
<br/><br/><label>LCCN: </label>l  22000308  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Hours of labor--United States.<br/>Wages--United States.<br/>Coal miners--United States.<br/>Coal mines and mining--United States.
<br/><br/><label>LC Class. No.: </label>HD8051  / .A62 no. 316