1. 3) The Japan Institute of Metals: Handbook of Steel Metal, (Maruzen, 1967) pp.68.
2. 4) M. kawakami: Metal material science and engineering (Lower volume), (Hozansha, 1959) pp.274-276.
3. 5) The Japan Science for Heat Treatment: Introduction to Heat Treatment Technology, (Taigashuppan, 1999) pp.178-193.