1. Department of Economics and Management, Southwest Petroleum University, Chengdu, Sichuan, China
2. Department of Economics, Zhejiang University, Hangzhou, Zhejiang, China
3. Post-Doctoral Research Station of Bank of China, Beijing, China
4. Post-Doctoral Station of Renmin University of China, Beijing, China
5. Department of Economics and Management, Southwest Jiaotong University, Chengdu, Sichuan, China