1. 1）H. Yasuda, T. Watanabe and M. Kunieda, Electric Furnace Steel of Japan, 46, p.147（1975）.
2. 2）K. Kawada, J. Jpn. Soc. Heat Treat., 25, pp.231-XXX（1985）.
3. 3）Liedtke.Dieter, translated by G. Miyamoto and N. Ishida, Nitriding and Nitrocarburizing on Iron Materials, Agne Technical Center, （2011）.
4. 4）Ebersbau.U, Härterei-Techn. Mitt., 54, S241（1999）.
5. 5）Spies H.J. and Winkler H.P., IfL-Mitt., 24, S101（1985）.