1. Department of Mathematics , Huzhou University , Huzhou 313000 , P. R. China
2. Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering, Changsha University of Science & Technology , Changsha 410114 , P. R. China
3. Department of Mathematics and Statistics , Riphah International University , I-14 , Islamabad 44000 , Pakistan
4. Department of Mathematics , Government College University Faisalabad , Layyah Campus , Layyah 31200 , Pakistan
5. Department of Mathematics , COMSATS University Islamabad , Sahiwal 57000 , Pakistan
6. Department of Mathematics , Institute of Arts and Science, Government College University Faisalabad, Chiniot Campus , Chiniot , Pakistan