1. Croney, D., Coleman, J. D. and Bridge, P. M. (1951) The measurement of the suction of moisture held in porous materials and its relationship to moisture content, Report, Road Research Laboratory, Crowthorne, England.
2. Danielson, R. E. and Sutherland, P. L. (1986) Porosity, Methods of Soil Analysis, Physical and Mineralogical Methods, Part 1, 2nd edition, Arnold Klute, ed., American Society of Agronomy, 443–460.
3. Diamond, S. (1970) Pore size distributions in clays, Clays and Clay Minerals, 18, 7–23.
4. Fredlund, D. G. and Morgenstern, N. R. (1976) Constitutive relations for volume change in unsaturated soils, Canadian Geotechnical Journal, 13, 261–276.
5. Fredlund, D. G. and Rahardjo, H. (1993) Soil Mechanics for Unsaturated Soil, John Wiley and Sons Inc., New York.