1. Engineering Rock Mass Classifications;Bieniawski,1989
2. Numerical modeling of yield zones in weak rocks;Duncan Fama,1993
3. Underground excavations in rock;Hoek;Inst. Min. Metall., London,1980
4. Support of Underground Excavations in Hard Rocks;Hoek,1995
5. IGME, 1993. Geological map of Greece, scale 1:500.000. Inst. Geol. Min. Expl. Gr.