1. Design of Underground Openings in Competent Rock;Obert;U.S. Bureau of Mines. Bull. 587,1960
2. Stresses around a wellbore due to internal pressure and unequal principal geostatic stresses;Galle;Soc. Petrol. Engr. J.,1962
3. Tunnel mechanics;Abel;Colo. Sch. Mines Q.,1967
4. The Conditions of the Ground Around Excavations in Hard Rock at Great Depth;Potts,1961
5. The Conditions of the Ground Around Excavations in Hard Rock at Great Depth;Denkhaus,1961