1. The description of rock masses of engineering purposes;Q. Jl Engng Geol.,1977
2. Suggested methods for the quantitative description of discontinuities in rock masses;International Society for Rock Mechanics;Int. J. Rock Mech. Min. Sci. & Geomech. Abstr.,1978
3. Discontinuities and rock mass geometry;Hudson;Int. J. Rock Mech. Min. Sci. & Geomech. Abstr.,1979
4. Describing the size of discontinuities;Cruden;Int. J. Rock Mech. Min. Sci. & Geomech. Abstr.,1977
5. Discontinuity spacings in crystalline rock;Wallis;Int. J. Rock Mech. Min Sci. & Geomech. Abstr.,1980