1. Faculty of Mechanics and Mathematics, National University of Uzbekistan, Vusgorodok, Tashkent, 100074, Uzbekistan
2. Department of Mathematics, Faculty of Science, University Putra Malaysia, Institute for Mathematical Research, University Putra Malaysia 43400, Serdang, Selangor, Malaysia
3. Department of Mathematics, Faculty of Science, University Putra Malaysia, Institute for Mathematical Research, University Putra Malaysia 43400, Serdang, Selangor, Malaysia