1. School of Finance and Business, Shanghai Normal University, Shanghai 200234, P. R. China
2. School of Finance, Anhui University of Finance and Economics, Bengbu 233030, P. R. China
3. School of Accounting, Anhui University of Finance and Economics, Bengbu 233030, P. R. China
4. School of Statistics and Applied Mathematics, Anhui University of Finance and Economics, Bengbu 233030, P. R. China