1. Yu. M. Lakhtin, "Surface hardening of steels and alloys," Metalloved. Term. Obrab. Met., No. 11, 14?25 (1988).
2. V. P. Glukhov Boride Coatings on Iron And Stesls [in Russian], Naukova Dumka, Kiev (1970).
3. L. G. Voroshnin and L. S. Lyakhovich, Boriding of Steel [in Russian], Metallurgiya, Moscow (1978).
4. A. P. Épik, L. A. Kotlyarenko, and V. D. Derkas, "Boriding ? an effective method of improving the wear resistance of a steel surface," in: Protective Coatings on Metals [in Russian], No. 2, Naukova Dumka, Kiev (1968), pp. 166?169.
5. M. Rile, "Causes of crack formation in borided layers of steel," Metalloved. Term. Obrab. Met., No. 10, 20?23 (1974).