1. School of Economics and Management, Sichuan Normal University, 1819 Chenglong Ave., Chengdu 610101, China
2. School of National Safety and Emergency Management, Beijing Normal University, 19 Xinjiekou Wai Ave., Beijing 100875, China
3. Faculty of Geographical Science, Beijing Normal University, 19 Xinjiekou Wai Ave., Beijing 100875, China
4. College of Management, Sichuan Agricultural University, 211 Huimin Road, Chengdu 611130, China