1. 12) M. KAWAI, K. KAWAGUCHI, H. YOSHIDA, E. KANAZAWA and S. MITO : J. Iron Steel Inst., 64 (1978), p. 128
2. 13) F. ITO, K. KUWABARA, M. MIYAZAKI, Y. FUKUI and Y. TAKEDA : Transactions of the ASME, 110 (1988), p. 127
3. 19) F. R. LARSON and J. MILLER : Trans. ASME, 74 (1952), p. 765
4. 20) T. MARRISON and A. HOGG : Proc. Creep Strength in Steel and High-temperature Alloys (1972), p. 242