1. Department of Mathematics, Kuwait University, Safat, Kuwait
2. School of Software, South China Normal University, Foshan, Guangdong, People's Republic of China
3. School of Mathematics and Statistics, Zhaoqing University, Zhaoqing, People's Republic of China
4. Department of Mathematics, Kuwait College of Science and Technology, Safat, Kuwait
5. FAMNIT, University of Primorska, Koper, Slovenia
6. Mathematics Department, TOBB University of Economics and Technology, Ankara, Turkey