1. Department of Mathematics, Huzhou University, Huzhou, P. R. China
2. Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering, Changsha University of Science & Technology, Changsha, P. R. China
3. Department of Mathematics, COMSATS University Islamabad, Attock, Pakistan
4. Department of Mathematics, COMSATS University Islamabad, Lahore, Pakistan
5. Department of Mathematics, Islamia College, Peshawar, Pakistan
6. Faculty of Education, Van Yuzuncu Yil University, Van, Turkey