1. College of Economics and Management, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 211106, P. R. China
2. School of Economics and Management, Fuzhou University, Fuzhou, Fujian 350108, P. R. China
3. The Financial Affairs Office of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530507, P. R. China