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2. 2) H. Masumoto, Y. Murakami and M. Hinai: J. Japan Inst. Metals, 35 (1971), 985 (in Japanese);
3. H. Masumoto, Y. Murakami and M. Hinai: Trans. JIM, 13 (1972), 182.
4. 3) M. Nishikawa: J. Inst. Electronics Communication Engrs. of Japan, 60 (1977), 1267 (in Japanese).
5. 4) T. Wakô: J. Mag. Society of Japan, 3 (1979), 13 (in Japanese).