1. Source Book on Nitriding, (ASM, Metals Park, Ohio, 1977).
2. P. Birk, Microtechnic 24 (1970) 277.
3. T. Bell, Heat Treatment of Metals 2 (1975) 39.
4. J. Zy?k, H�rterei-Tech. Mitt. 31 (1976) 137.
5. K. Sachs and D. B. Clayton, Heat Treatment of Metals 6 (1979) 29.