[1] Lanzhou Univ, Sch Econ, Lanzhou 730000, Peoples R China
[2] Univ Chinese Acad Sci, Sch Publ Policy & Management, Beijing, Peoples R China
[3] Lanzhou Univ, Sch Management, Lanzhou 730000, Peoples R China
[4] Zhejiang Sci Tech Univ, Sch Econ & Management, Hangzhou 310018, Peoples R China
[5] Anhui Univ Finance & Econ, Sch Stat & Appl Math, Bengbu, Peoples R China