1. Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P. O. Box 55134-441, Maragha, Iran
2. Department of Mathematics, Institute of Applied Sciences and Humanities, GLA University, Mathura 281406, Uttar Pradesh, India
3. Department of Mathematical Sciences, University of Zululand, Kwa-Dlangezwa 3886, South Africa