1. Postdoctoral research fellow, School of Public Policy and Management, Tsinghua University, Beijing, 100190, China P.R.
2. Associate Professor, Department of Economics, University of New Mexico, 1915 Roma Ave. NE 1019, Albuquerque, NM 87131, USA.
3. Professor, Department of Agricultural Economics and Rural Development, University of Göttingen, Platz Der Göttinger Sieben 5, 37073 Göttingen, Germany.