1. W.O. Smith, P.D. Foote, P.F. Busang, Phys. Rev. 34, 1271 (1929)
2. T. Kallstenius, W. Bergau, Proc. 5th Int. Conf. Soil Mech. Found. Eng. 1, 165 (1961)
3. T. Mogami, Soils Found. 5, 26 (1965)
4. M. Oda, Soils Found. 14, 13 (1974)
5. C.B. Brown, “The use of maximum entropy in the characterization of granular materials”, in Continuum Mechanical and Statistical Approaches in the Mechanics of Granular Materials, edited by C.S. Cowin, M. Satake (Gakujutsu Bunken Fukyu-kai, 1978), p. 98