Funding for this research was provided by:
National Natural Science Foundation of China (Grant No. 41571527)
National Natural Science Foundation of China (No. 41601614)
National Natural Science Foundation of China (No. 41701622)
National Natural Science Foundation of China (41801221)
the Sichuan Center for Rural Development Research Project (No. 01781912)
Article History
Accepted: 13 November 2018
First Online: 17 November 2018