1. School of Mathematics and Statistics, Nanjing University of Information Science & Technology, Nanjing, People's Republic of China
2. Department of Statistics, School of Economics, Xiamen University, Xiamen, People's Republic of China
3. Key Laboratory of Econometrics, Ministry of Education, Xiamen University, Xiamen, People's Republic of China
4. Wang Yanan Institute for Studies in Economics, Xiamen University, Xiamen, People's Republic of China