1. Çankaya University, Department of Mathematics, 06790 Etimesgut, Ankara, Turkey
2. Department of Mathematics and General Sciences, Prince Sultan University, P. O. Box 66833, Riyadh 11586, Saudi Arabia
3. Department of Medical Research, China Medical University, Taichung 40402, Taiwan
4. Department of Computer Science and Information Engineering, Asia University, Taichung, Taiwan
5. Department of Mathematics, University of Malakand, Khyber Pakhtunkhwa, Pakistan