Institution: | 1. School of Sciences, Jimei University, Xiamen 361021, China;2. Department of Mathematics, Faculty of Science, Universiti Brunei Darussalam, Gadong BE 1410, Brunei Darussalam;3. Department of Mathematics, Xinyang Normal University, Xinyang 464000, China;4. Department of Mathematics, Wenzhou University, Wenzhou 325003, China |