1. S. V. Serensen, ?Fatigue resistance in connection with hardening and design factors,? in: Increasing the Fatigue Strength of Machine Parts by Surface Treatment [in Russian], Mashgiz, Moscow (1952), p. 7.
2. B. F. Balashov, ?Nitriding as a method of increasing the strength of machine parts,?-ibidIncreasing the Fatigue Strength of Machine Parts by Surface Treatment [in Russian], Mashgiz, Moscow (1952), p. 71.