1. R. W. Landgraf: ASTM STP 467, p. 3, ASTM, Philadelphia, 1970.
2. C. E. Feltner and P. Beardmore: ibid, p. 77.
3. C. E. Feltner and R. W. Landgraf:J. Basic Eng., 1971, vol. 93, p. 441.
4. E. Dowling:J. Mater., 1972, vol. 7, p. 71.
5. E. R. Morgan, T. E. Dancy, and M. Korchynsky:Metal Progr., 1966, vol. 89, p. 125.