1. L. S. Lyakhovich and L. G. Voroshnin, Boronizing of Steel [in Russian], Metallurgiya, Moscow (1967).
2. J. O. Bockris and G. Mellors, J. Phys. Chem.,60, No. 9 (1956).
3. G. Ostroumov, Zh. Obshch. Khim.,19, No. 3 (1949).
4. L. Pei-Cing et al., J. Physics and Chemistry of Glasses,1, No. 6 (1960).
5. W. Kroll, Z. Phys. Chem.,102, No. 1 (1918).