Sampath Kumar, T. <br/><br/>
Desirable illumination levels in Indian coal mines :  an investigation / 
T. Sampath Kumar and M. R. Paul 
 - Dhanbad :  Central Mining Research Station,  1966 
 - 15 p. ;  21 cm. 
 - Reference Central Mining Research Station-V13/29 .
<br/><br/><label>Dewey Class. No.: </label>622.(54)