1. Abe, H. (1994). Experimental study on the evaluation method of mechanical property for unsaturated soil, Doctoral Dissertation, University of Tokyo (In Japanese).
2. Abe, H. and Hatakeyama, M. (1997). “Report of the committee for valuation of water permeability in unsaturated ground.” Journal of Japanese Geotechnical Society, pp. 82–88 (In Japanese).
3. Bjerrum, L. (1973). “Problems of soil mechanics and construction on soft clay and structurally unstable soils.” Proc. of the 8th International Conference on soiI Mechanics and Foundation Engineering, Vol. 3, pp. 111–159.
4. Fredlund, D. G. and Morgenstern, N. R. (1976). “Constitutive relations for volume change in unsaturated soils,” Canadian Geotechnical Journal, Vol. 13, No. 3, pp. 261–276.
5. Fredlund, D. G., Morgenstern, N. R., and Widger, R. A. (1978). “The shear strength of unsaturated soils.” Canadian Geotechnical Journal, Vol. 15, No. 3, pp. 313–321.