Rad, Parviz F. <br/><br/>
Mechanical properties and cutting characteristics of coal / 
by Parviz F. Rad 
 - Washington, D. C. :  Uniteds States Government Printing Office,  1973 
 - ii, 46 p. ;  26 cm. 
 - Information circular ;  8584 .
<br/><br/> Bureau of mines 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mechanical engineering<br/>Mechanical movements
<br/><br/><label>Dewey Class. No.: </label>621