D. A. Bakeev
Lipetsk State Pedagogical University named after P.P. Semenov-Tyan-Shansky
Russian Federation

Dmitry A. Bakeev, Post-Graduate Student of the Department of Mathematics and Physics

42 Lenina Str., Lipetsk 398020

V. V. Filippov
Lipetsk State Pedagogical University named after P.P. Semenov-Tyan-Shansky; Moscow State University of Technologies and Management named after K.G. Razumovsky (First Cossack University), Lipetsk branch
Russian Federation

Vladimir V. Filippov, Doctor of Science (Physics and Mathematics), Professor of the Department Mathematics and Physics; Professor of the Department of Natural and Technical Sciences

42 Lenina Str., Lipetsk 398020

4 Krasnoznamennaya Str., Lipetsk 398006