Obert, Leonard ,1906- Duvall, Wilbur I. <br/><br/>
Rock mechanics and the design of structures in rock 
[by] Leonard Obert [and] Wilbur I. Duvall 
 -  Wiley New York  1967  [1967] 
 - xix, 650 p. : illus. ; 24 cm. 
<br/><br/> Includes bibliographies & index 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Rock mechanics<br/>Underground construction--TA
<br/><br/><label>LC Class. No.: </label>TA706.O2