1. 1) T. Irita, M. Isoyama, Y. Hara, Y. Okuno, Y. Kanayama and K. Tashiro: Tetsu-to-Hagané, 68 (1982), No.15, 2295.
2. 2) Y. Togino, M. Sugata, I. Abe, K. Yamaguchi and M. Nakamura: Tetsu-to-Hagané, 65 (1979), No. 10, 1536.
3. 3) K. Okumura, T. Kai, H. Marushima, H. Takahashi and J. Kurihara: Trans. Iron Steel Inst. Jpn., 22 (1982), 243.
4. 4) M. Iizuka, S. Kishimoto, T. Shibuya and T. Fukushima: Tetsu-to-Hagané, 66 (1980), No. 13, 1966.
5. 5) Y. Togino, M. Toteoka, M. Sugata, K. Yamaguchi, S. Kume, K. Yamaguchi and I. Abe: Tetsu-to-Hagané, 65 (1979), No. 10, 1553.