1 Division of Dynamics, Technical University of Lodz, Stefanowskiego 1/15, 90-924 Lodz, Poland.
2 Faculty of Mathematics and Mechanics, St. Petersburg State University, 198504 Peterhof, St. Petersburg, Russia; Department of Mathematical Information Technology, University of Jyväskylä, 40014 Jyväskylä, Finland; Institute for Problems in Mechanical Engineering of the Russian Academy of Sciences, 199178 St. Petersburg, Russia. Electronic address: nkuznetsov239@gmail.com.
3 Faculty of Mathematics and Mechanics, St. Petersburg State University, 198504 Peterhof, St. Petersburg, Russia.