1. Barton NR, Lien R, Lunde J (1974) Engineering classification of rock masses for the design of tunnel support. Rock Mech 6(4):189–239
2. Bieniawski ZT (1973) Engineering classification of jointed rock masses. Trans S Afr Inst Civ Eng 15:335–344
3. Brown ET (ed) (1981) Rock characterization, testing and monitoring—ISRM suggested methods. Pergamon, Oxford, pp 171–183
4. Cai M, Kaiser PK, Uno H, Tasaka Y, Minami M (2004) Estimation of rock mass strength and deformation modulus of jointed hard rock masses using the GSI system. Int J Rock Mech Min Sci 41(1):3–19
5. Chandler RJ, de Freitas MH, Marinos P (2004) Geotechnical characterization of soils and rocks: a geological perspective. Advances in geotechnical engineering: the Skempton conference, vol 1, Thomas Telford, London, pp 67–102