1Center for Chinese Agricultural Policy, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
2Department of Agricultural and Resource Economics, University of CA, Davis 95616, USA
3State Key Laboratory and Division of Preventive Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510275, China
4ORBIS International, NY 10018, USA
5School of Economic Management, Xibei University, Xi'an 710127, China
6School of Agricultural Economics and Rural Development, Renmin University of China, Beijing 100872, China
7International Business School, Shaanxi Normal University, Xi’an, 710062, China
8Stanford University, Stanford 94305, USA