1. T. M. Chang andH. W. Swift,J. Inst. Metals 78 (1950?51) 119.
2. O. W. Boston, ?Metal Processing?, 2nd edn. (Wiley, New York, 1951).
3. A. G. Atkins andD. K. Felbeck,Chartered Mech. Engr. (1974) 78.
4. K. M. Ngan, Ph.D. Dissertation, University of Hong Kong (1971).
5. Y. W. Mai,J. Mater. Sci. 10 (1975) 1271.