1. Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region, Russia
2. Institute for Information Transmission Problems of the Russian Academy of Sciences (Kharkevich Institute), Moscow, Russia
3. Novosibirsk State University, Novosibirsk, Russia
4. Sobolev Institute of Mathematics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
5. Tomsk State University, Tomsk, Russia