S.N. Trushkov1, V.V. Kuptsov2, O.A. Shmonin3, K.A. Ponur4

1-4 Lobachevsky State University of Nizhny Novgorod (Nizhny Novgorod, Russia)

1 trushkovsn@gmail.com; 2 vitaliy.kuptsov.nn@yandex.ru; 3 olgsh6@yandex.ru; 4 ponur0kirill@gmail.com