1. School of Management Science and Engineering, Nanjing University, Nanjing 210093, China
2. Ibn Zohr University, Présidence, BP 32/S, 80000 Agadir, Morocco
3. Mathematics Department, Faculty of Sciences, COMSATS Institute of Information Technology, Plot no. 30, Sector H-8, Islamabad, Pakistan
4. Mathematics Department, College of Basic Education, Main Campus, Shamiyah, Adiliya 73251, Kuwait