1. Shields, A., Mitt. Preuss. Vers. Anst. Wasserb. u. Schiffb., Berlin, Heft, 26 (1936).
2. Bagnold, R. A., Phil. Trans. Roy. Soc., A, 249, 248 (1956).
3. Raudkivi, A. J., Loose Boundary Hydraulics, 23 (Pergamon Press, London, 1967).
4. Tison, L. J., Ann. Soc. Tech., Brux., Ser. 1, 61, 163 (1947).
5. Liu, H. K., J. Hydr. Div. A.S.C.E., 83, No. HY2 (1957).