1) Bishop, A.W. (1958): "Test requirement for measuring the coefficient of earth pressure at rest," Proc. on Earth Pressure Problems, Brusseles, Vol.1, pp.2-14.
3) Bjerrum, L. (1973): "Problems of soil mechanics and construction on soft clays and structurally unstable soils (collapsible, expansive and others)," 8th ICSMFE, Moscow, pp. 111-159.