1. Faculty of Basic Science, University of Bonab, Bonab, Iran
2. Department of Mathematics, College of Education in Jubail, Imam Abdulrahman Bin Faisal University, P.O. 12020, IndustrialJubail31961, Saudi Arabia; and Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
3. Department of Mathematics, Atilim University, 06836 Incek, Ankara, Turkey