[Yang, Xin; Liu, Sheng; Jin, Cheng; Huang, Chuangxia] Changsha Univ Sci & Technol, Sch Math & Stat, Changsha, Hunan, Peoples R China.
[Yang, Xin] Changsha Univ Sci & Technol, Sch Econ & Management, Changsha, Hunan, Peoples R China.
[Cao, Jie] Tianjin Univ, Coll Management & Econ, Tianjin, Peoples R China.
[Cao, Jie; Cao, J] Tianjin Univ, Coll Management & Econ, 92 Weijin Rd, Tianjin 300072, Peoples R China.