E.N. Diskaeva - Ph.D. (Phys.-Math.), Associate Professor, Department of Humanities, Natural Sciences and Legal Disciplines, University of Stavropol (Stavropol). E-mail: diskaevapes@mail.ru Yu. A. Boyko - Ph.D. (Phys.-Math.), Specialist of Scientific Information and Analytical Work, Department of Research and International Cooperation, University of Stavropol (Stavropol). E-mail: boykoya@bk.ru