1. Engineering classification of rock masses for the design of tunnel support;Barton;Rock Mech.,1974
2. Rock mass classifications in rock engineering;Bieniawski,1976
3. A survey of large permanent underground openings in Norway;Brekke,1970
4. The siting of mine tunnels;Cook;Assoc. Mine Managers,1973
5. The effects of natural geologic discontinuities on behavior of rock in tunnels;Cording,1974