1. Bagnold, R. A., The Physics of Blown Sand and Desert Dunes, Methuen, London, 1954.
2. Prandtl, L., Z. Ver. Deut. Ing., 1933, 77, 105; see also 1, and Townsend, A. A., The Structure of Turbulent Shear Flow, Cambridge Univ. Press, London, 1956.
3. Bagnold, R. A., Proc. Roy. Soc. (London), 1954, A225, 49.
4. Roscoe, R., in Flow Properties of Disperse Systems (by J. J. Hermans), North Holland Publishing Company, Amsterdam, 1953.
5. Karnis, A., Goldsmith, H. L. and Mason, S. E.,J. Colloid Interf. Sci., 1966, 22, 531.