Raju, N. M. <br/><br/>
Roof bolting anchorage efficiency of 22 mm diameter wedge and slot type roof bolts in a group of collieries / 
N. M. Raju and Dr. B. Singh 
 - Dhanbad :  Central Mining Research Station,  1967 
 - 20 p. :  ill. ;  21 cm. 
 - Reference Central Mining Research Station-M18/37 .
<br/><br/><label>Dewey Class. No.: </label>622.(54)