1. College of Economics, Sichuan Agricultural University, Chengdu, P.R. China
2. Postdoctoral Station of Management Science and Engineering, College of Economics and Management, Nanjing University of Aeronautics and Astronautics, Nanjing, P.R. China
3. School of Economics, Zhejiang University, Hangzhou, P.R. China
4. Department of Business Administration, Sukkur IBA University, Sukkur, Pakistan
5. School of Economics, Lanzhou University, Lanzhou, P.R. China