1. A. H. S. Ang and W. H. Tang, “Probability concepts in engineering planning and design,: in: Decision Risk and Reliability, II, John Wiley and Sons, New York (1984).
2. J. R. Benjamin and C. A. Cornell, Probability, Statistics and Decision for Civil Engineers, MacGraw-Hill, New York (1970).
3. E. H. Vanmarcke, “Probabilistic modeling of soil profiles,” J. Geotechnical Engineering, ASCE 103, GT 11, November (1977).
4. N. M. Pokrovsky, Driving Horizontal Workings and Tunnels, Mir, Moscow (1980).
5. N. Barton and Rand Lunde J. Lien, “Engineering classification of rock masses for the design of tunnel support,” Rock Mechanics, No. 6 (1974).