1. Department of Mathematics, Azarbaijan Shahid Madani University, Tabriz, Iran
2. Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
3. Laboratory of Applied Mathematics, Kasdi Merbah University, B.P. 511.30000, Ouargla, Algeria
4. Department of Mathematics, K. N. Toosi University of Technology, P.O. Box 16315-1618, Tehran 15418, Iran