9R. A. S. Johnson. Mining at ultra - depth, evaluation of alternatives [ A ]. In :Proceedings of the 2nd North America Rock Mechanics Symposium[ C ]. Montreal: NARMS' 96, 1996 : 359 - 366.
10M. Vogel, H. P. Andrast. Alp transit- safety in construction as a challenge, health and safety aspects in very deep tunnel construction [J]. Tunneling and Underground Space Technology, 2000,15 (2) : 147 -151.