1. 1. The Japan Machinery Federation and Osaka Science and Technology Center (1992 ) Report on promotion testing and evaluation of surface treated metallic materials. Report No. NIKKIREN-3-SENTAN-2(1992), (in Japanese).
2. 2. K. Tokaji, T. Ogawa, and H. Shibata . The effect of gas nitriding on fatigue behaviour in pure titanium . Int. J. Fatigue, in press.
3. 3. H. Shibata, K. Tokaji, T. Ogawa, and C. Hori . The effect of gas nitriding on fatigue behaviour in titanium alloys . Int. J. Fatigue, in press.
4. 4. The Japan Society of Precision Engineering, Surface Treatment Technology (1988 ) The Nikkan Kougyou Shinbun, Tokyo, (in Japanese).