1. Institute for Advances Study in Mathematics, Harbin Institute of Technologies, Harbin, People's Republic of China
2. North Caucasus Center for Mathematical Research, Vladikavkaz, Russia
3. Karakalpak State University, Nukus, Uzbekistan
4. V. I. Romanovskiy Institute of Mathematics Uzbekistan Academy of Sciences, Tashkent, Uzbekistan
5. Central Asian University, Tashkent, Uzbekistan