Khanty-Mansiysk ZaikinAlexanderVasilievich Ugra State University, Khanty-Mansiysk, 16 Chekhov St., Khanty-Mansiysk 628012, Russia zav20001@mail.ru Read more about Zaikin Alexander Vasilievich DukhnovskySergeyVitalievich Ugra State University, Khanty-Mansiysk, 16 Chekhov St., Khanty-Mansiysk 628012, Russia dukhnovskysv@mail.ru Read more about Dukhnovsky Sergey Vitalievich
