1. Ashley D. B. et al. (1981). “Geological prediction and updating in tunneling—A probabilistic approach.” Rock mechanics From research to implementation 22nd U.S. Symposium on Rock Mechanics MIT Cambridge Mass.
2. Chan M. H. C. (1981). “A geological prediction and updating model in tunneling ” thesis presented to the Massachusetts Institute of Technology at Cambridge Mass. in partial fulfillment of the requirements for the degree of Master of Science.
3. Cox D. R. and Miller H. D. (1965). The theory of stochastic processes . Methuem and Co. Ltd. London U.K.
4. Einstein H. H. et al. (1983). “Comparison of five empirical tunnel classification methods—Accuracy effects of subjectivity and available information.” Proc. 5th Int. Cong. of the Int. Soc. for Rock Mech. Melbourne Apr. 1983 Balkema Publishers Rotterdam.
5. Howard R. A. (1960). Dynamic programming and Markov processes . MIT Press Cambridge Mass.