Affiliation: | 1. School of Mathematics, Hefei University of Technology, Hefei, China;2. Shandong University Qilu Securities Institute for Financial Studies, Shandong University, Jinan, China;3. Shandong University Qilu Securities Institute for Financial Studies, Shandong University, Jinan, China;4. School of Economics, Hefei University of Technology, Hefei, China |