1. 1) Manufactured by the Elgin National Watch Co. U.S.A. 40Co–25Cr–22Ni–0.03Be–(0.15∼0.20)C–2Mn–bal Fe system alloys.
2. 2) M. F. Straumann: Soc. Suisse de Chronom., (1954), 209;
3. M. E. Dubois: Soc. Suisse de Chronom., (1954), 215;
4. J. Satô, K. Ikeda and N. Kamata: J. Japan Chronom. Soc., 12 (1961), 39, etc.
5. 3) H. Masumoto, H. Saitô and T. Kobayashi: Japan Patent, No. 230713 (Dec. 14, 1956).