1. School of Mathematics, China University of Mining and Technology, Xuzhou, 221116, China
2. College of Science, Princess Nourah Bint Abdul Rahman University, Riyadh, PO Box 84428, Saudi Arabia
3. Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Via dei Musei 41, Brescia, Italy
4. College of Mathematica and Statistics, Chongqing Jiaotong University, Chongqing 400074, China