1. Department of Mathematics, Government Model Science College, Rewa 486 001 (M.P.), India
2. Department of Mathematics, Government College, Bandri, Sagar, 470442 (M.P.), India
3. Department of Mathematical Sciences, University of Zululand, P. Bag X1001, Kwa-Dlangezwa 3886, South Africa
4. Faculty of Natural Sciences, Mangosuthu of Technology, P. O. Box 12363, Jacobs 4026, South Africa
5. National Institute for Theoretical and Computational, Sciences (NITheCS), South Africa
6. Department of Mathematics, AKS University, Satna (M.P.), India