1. 1) Japan Industrial Standards: JIS G 0562, Method of measuring nitrided case depth for iron and steel.
2. 2) C. H. Knerr, T. C. Rose and J. H. Filkowski: Gas Nitriding, ASM Handbook Vol. 4, Heat Treating, (ASM International, 1990) pp. 387–409.
3. 3) C. F. Floe: Method of nitriding, US 2437249, (1948).
4. 4) The Japan Society for Heat Treatment (Ed.): Heat treatment technology, (Nikkan Kogyo Shinbun Ltd., 2000) pp. 211–239.
5. 5) M. Sumida: J. Jpn. Soc. Heat Treat. 51 (2011) 273–282.