2) Committee of JSSMFE on the Test Method of Relative Density of Sand (1979): "Maximum-minimum density test method of sand," Procedures for Testing Soils, 2nd Revised Edition, JSSMFE, Part 2, Chapter 9, pp.172-188 (in Japanese).
3) Curray, J.R. (1956): "The analysis of two-dimensional orientation data," Journal of Geology, Vol.64, pp. 117-131.