1. Faculty of Mathematics, K. N. Toosi University of Technology, P.O. Box 16315-1618, Tehran, Iran
2. Nonlinear Analysis Research Group, Ton Duc Thang University, Ho Chi Minh City, Vietnam
3. Faculty of Mathematics and Statistics, Ton Duc Thang University, Ho Chi Minh City, Vietnam
4. China Medical University Hospital, China Medical University, Taichung 40402, Taiwan