Obert, leonard Duvall, Wilbur I. <br/><br/>
Rock mechanics and the design of structures in rock 

 - London  John wiley  1967 
 - 650p. 
<br/><br/><label>Subjects--Uniform Titles: </label><br/>rock mechanics
<br/><br/><label>Dewey Class. No.: </label>552  / Q15R