Virgin, R. Z. <br/><br/>
Coal-mine ventilation. 

 - Washington, D.C. :  Federal Board for Vocational Education :  Govt. Print. Off.,  1920. 
 - 63 p., [3] leaves of plates :  ill ;  24 cm. 
 - Bulletin / Federal Board for Vocational Education ;  no. 41 Trade and industrial series ;  no. 11 .
<br/><br/> Cover title.  "Prepared by R.Z. Virgin"--P. 5.  "November, 1919." 
<br/><br/><label>LCCN: </label>e  20000544  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mine ventilation.
<br/><br/><label>LC Class. No.: </label>LC1045  / .A25 no. 41