1. R. D. Williams:Trans. ASM, 1960, vol. 52, p. 530.
2. W. Gruhl and R. Fischer:Z. Metallic., 1955, vol. 46, p. 742.
3. B. Lynch: Ph.D. Thesis, Aston University, U.K.
4. W. Koster and W. Knorr:Z. Metallic., 1954, vol. 45, p. 350.
5. S. Nishkawa, N. Nagata, and S. Kobayashi:Nippon Kinzoku Gakkaishi, 1966, vol. 30, p. 302.