1. Department of Economics, Lingnan University, Hong Kong, China HKG
2. Department of Economics, School of Economics and Management, National Center for Economic Research at Tsinghua University, Tsinghua University, Beijing 100084, China
3. Department of Economics, School of Economics and Management, Tsinghua University, Beijing 100084, China
4. Department of Economics, Hong Kong University of Science and Technology, Hong Kong, China HKG
5. Department of Economics, National University of Singapore, Singapore 117570, Singapore