1. Department of Mathematics & Statistics, International Islamic University Islamabad, Islamabad, Pakistan
2. NUIST Reading Academy, 219 Ningliu Road, Nanjing, Jiangsu 210044, China
3. Institute of Research and Development of Processes, Faculty of Science and Technology, Univeraity of the Basque Country Campus of Leioa (Bizkaia), 644-Leioa, Spain
4. Department of Mathematics, COMSATS University Islamabad, Attock Campus, Attock, Pakistan