O. M. Brehov, A. V. Korneenkova, K. A. Kordover, N. Y. Muhin, E. A. Orlova, I. V. Tuzov
E.V. Semina - Post-graduate Student, Department of Applied Mathematics, Moscow State University of Eco-nomics, Statistics and Informatics. E-mail: semina_elisaveta@mail.ru