[1] Ball State Univ, Dept Econ, Muncie, IN 47306 USA
[2] Tsinghua Univ, Sch Econ & Management, Beijing, Peoples R China
[3] Santander Bank, Dorchester, MA USA
[4] Penn State Univ, Dept Energy & Mineral Engn, University Pk, PA 16802 USA
[5] Penn State Univ, EMS Energy Inst, University Pk, PA 16802 USA