1. Department of Mathematical Sciences, North-West University, Private Bag X 2046, Mmabatho 2735, South Africa
2. Department of Engineering Sciences, Faculty of Technology and Engineering, East of Guilan, University of Guilan, Rudsar 44891-63157, Iran
3. School of Electronics and Information Engineering, Wuhan Donghu University, Wuhan 430212, China
4. Department of Mathematics, Rasht Branch, Islamic Azad University, Rasht, Iran