[1] China Univ Petr, Sch Business Adm, Beijing 102249, Peoples R China
[2] Rutgers State Univ, Dept Agr Food & Resource Econ, New Brunswick, NJ 08901 USA
[3] China Univ Petr, State Key Lab Heavy Oil Proc, Beijing 102249, Peoples R China
[4] Univ Int Business & Econ, Sch Int Trade & Econ, Beijing 100029, Peoples R China