1. L. Raymond, W. W. Gerberich and C. F. Martin, Proceedings of the 2nd International Symposium on High Strength Materials, Berkeley (Wiley, New York, 1965) p. 297.
2. R. Phillips and W. E. Duckworth, ??ibid, p. 307.
3. G. Thomas, D. Schmatz and W. W. Gerberich, ??ibid, p. 251.
4. W. Justusson and D. Schmatz, Trans. Amer. Soc. Metals 35 (1962) 640.
5. S. J. Harris and N. R. Nag, J. Mater. Sci. 10 (1975) 1137.