1. Scientific and Educational Mathematical Center “Mathematics of Future Technologies,” Lobachevsky State University of Nizhny Novgorod, 23 Gagarina Ave., 603950 Nizhny Novgorod, Russia
2. Laboratory of Dynamical Systems and Applications, National Research University Higher School of Economics, 25/12 Bolshaya Pecherskaya Ulitsa, 603155 Nizhny Novgorod, Russia
3. Kotelnikov’s Institute of Radio-Engineering and Electronics of RAS, Saratov Branch, Zelenaya 38, Saratov 410019, Russia