1. Goodman, R.E., 1989, Introduction to Rock Mechanics, second edition. John Wiley and Sons, New York, p. 562.
2. Kanagawa, T., Hibino, S. and Ishida, T., 1986, In-situ stress measurements by overcoring method-Development of 8-element gauge for three-dimensional estimation. CRIPEI Report E385033. (in Japanese with English abstract)
3. Kaneko, K., Noguchi, H., Koga, M. and Hirayama, T., 1995, Effect of initial stress on rock slope failure. Journal of the Mining and Materials Processing Institute of Japan, 111, 761–776. (in Japanese with English abstract)
4. Leeman, R.E. and Hayes, D.J., 1966, A technique for determining the complete state of stress in rock using a single borehole. Proceedings of 1st Congress on International Society of Rock Mechanics (Expanded Abstract), Lisbon, p. 17–24.
5. Mohr, H.F., 1956, Measurement of rock pressure. Mine and Quarry Engineering, 22, 178–189.