1. 1) Y. Imai and T. Murata: J. Japan Inst. Metals, 29 (1965), 1053.
2. 2) T. Murata and Y. Imai: Sci. RITU, Tohoku University, A 25 (1974–1975), 103.
3. 3) K. Miyahara and Y. Ishida: Rep. Inst. of Industrial Science, Tokyo University, (Seisan-Kenkyu), 21 (1969), 580.
4. 4) N. Igata, K. Miyahara and T. Taoka: Jernkont. Ann., 155 (1971), 373.
5. 5) T. Murata and Y. Imai: Trans. JIM, 17 (1976), 43.