1. V.I.Romanovski Institute of Mathematics Uzbekistan Academy of Sciences, Tashkent, Uzbekistan
2. National University of Uzbekistan, Tashkent, Uzbekistan + New Uzbekistan University, Tashkent, Uzbekistan + V.I. Romanovski Institute of Mathematics Uzbekistan Academy of Sciences, Tashkent, Uzbekistan
3. Faculty of Computer and Mathematical Sciences, Universiti Teknologi MARA (UiTM), Shah Alam, Selangor Darul Ehsan, Malaysia
4. bNational University of Uzbekistan, Tashkent, Uzbekistan