Hartman, Howard L. <br/><br/>
Bulletin of the Mineral Experiment Station  Mining Engineering Series 

 - Pennsylvania  The Pennsylvania State University  1961 
 - 235p. 
<br/><br/><label>Subjects--Uniform Titles: </label><br/>Rock Mechanics
<br/><br/><label>Dewey Class. No.: </label>624.1513  / S99R