1. A. F. Zhigach et al., "Surface saturation of steel with boron from a gaseous medium,? Metalloved. Term. Obrab. Met., No. 4, 45 (1959).
2. M. A. Pchelkina and Yu. M. Lakhtin, "Gas boriding in boron trichloride,? Metalloved. Term. Obrab. Met., No. 7, 40 (1960).
3. L. N. Skugorova et al., "Gas boriding equipment and technology,? Metalloved. Term. Obrab. Met., No. 5, 61 (1972).
4. L. N. Skugorova et al., "Investigation of the gas boriding process,? Metalloved. Term. Obrab. Met., No. 11, 61 (1973).
5. A. V. Smirnov et al., "Pore formation in gas boriding,? in: Protective Coatings on Metals [in Russian], Naukova Dumka, Kiev (1979).