1. Theoretical Soil Mechanics;Terzaghi,1943
2. The Stability of Tunnels in Soft Rock at Depth;Wilson,1977
3. The behaviour of broken rock under triaxial compression;Hobbs;Int. J. Rock Mech. Min. Sci.,1970
4. Appendix 1 of a Study of Yield Zones around Roadway;Airey;NCB Final Report on ECSC Research Project 6220-AB/8/802,1977
5. Geological Society Engineering Group Working Party report on the logging of rock cores for engineering purposes