Institution: | School of Mathematics and Statistics, Northeast Normal University, Changchun, Jilin 130024, China,School of Mathematics and Statistics, Northeast Normal University, Changchun, Jilin 130024, China,School of Statistics and Mathematics, Shanghai Lixin University of Accounting and Finance, Shanghai, 201209, China and School of Mathematics and Statistics, Northeast Normal University, Changchun, Jilin 130024, China |