1. Standard test method for determination of the point load strength index of rock;ASTM,2002
2. Some effects of scale on the shear strength of joints;Barton;Int. J. Numer. Anal. Met.,1980
3. Engineering classification of rock masses for the design of tunnel support;Barton;Rock Mech.,1974
4. Rock mass classification in rock engineering;Bieniawski,1976
5. Rock Mechanics for Underground Mining;Brady,1985