1. School of Economics and Management, Tianjin University of Technology and Education, Tianjin 300222, P. R. China
2. College of Management and Economics, Tianjin University, Tianjin 300072, P. R. China
3. School of Business, Shandong Jianzhu University, Jinan 250101, P. R. China
4. School of Management, ShijiaZhuang Tiedao University, ShijiaZhuang 050043, P. R. China