1. Department of Finance, Economics and Management School of Wuhan University, Wuhan City, Hubei Province, China
2. Department of Applied Mathematics, Faculty of Mathematical Sciences, University of Tabriz, Tabriz, Iran
3. Department of Mathematics, Faculty of Science, University of Zakho, Zakho, Iraq
4. Department of Mathematics, College of Basic Education, University of Duhok, Zakho Street 38, 1006 AJ Duhok, Iraq