1. College of Continuing Education and Open College, Guangdong University of Foreign Studies, Guangzhou 510420, China
2. Science College, Hunan Agricultural University, Changsha 410128, China
3. School of Economics and Management, South China Normal University, Guangzhou 510006, China
4. Modern Business and Management Department, Guangdong Construction Polytechnic, Guangzhou 510440, China
5. School of Mathematics and Statistics, Central South University, Changsha 410083, China