1. Research Center for Primary Health Development and General Practice Education, Jiangsu Vocational College of Medicine, Yancheng, Jiangsu, China (mainland)
2. VIP Internal Medicine, The First Hospital of Lanzhou University, Lanzhou, Gansu, China (mainland)
3. Department of Health and Social Behavior, West China School of Public Health, Sichuan University, Chengdu, Sichuan, China (mainland)