1. Sobolev Institute of Mathematics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2. Novosibirsk State Agrarian University, Dobrolyubova
street, Novosibirsk, Russia
3. Regional Scientific and Educational Mathematical
Center of Tomsk State University, Tomsk, Russia
4. Lomonosov Moscow State University, Moscow, Russia
5. Demidov Yaroslavl State University, Yaroslavl,
Russia