Пастух, І., and Г. Соколова. “Concept of Research of the Wear Resistance of Metal Parts, Nitrided in Glow Discharge With Independent Parameters.”. Problems of Tribology, Vol. 76, no. 2, June 2015, pp. 69-73, http://tribology.khnu.km.ua/index.php/ProbTrib/article/view/430.