1. School of Management and Economics, Beijing Institute of Technology, Beijing 100081 China and also with the School of Economics and Management, Zhongyuan University of Technology, Zhengzhou 451191 China (e-mail: 76018111@bit.edu.cn).
2. Public Policy and Management, University of Chinese Academy of Sciences, Beijing 100049 China (e-mail: liuyun@ucas.ac.cn).
3. Library, Zhongyuan University of Technology, Zhengzhou 451191 China (e-mail: 3940@zut.edu.cn).