1. Department of Mathematics, Faculty of Science, Gazi University, Teknikokullar, TR-06500 Ankara, Turkey.
2. Department of Mathematics, Faculty of Science, Assiut University, Assiut 71516, Egypt; Department of Mathematics, College of Science and Arts at Unaizah, Qassim University, Qassim, Kingdom of Saudi Arabia.
3. Department of Mathematics and Statistics, University of Victoria, Victoria, British Columbia V8W 3R4, Canada; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 40402, Taiwan, Republic of China.