1. School of Public Health, Peking University, Beijing 100191, China
2. Brown School, Washington University in St. Louis, St. Louis, MO 63130, USA
3. Center of Health System and Policy, Institute of Medical Information & Library, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100020, China
4. Department of Health Services Research and Policy, London School of Hygiene & Tropical Medicine, London WC1H 9SH, UK
5. School of Basic Medicine Science, Shandong University, Jinan 250012, China
6. School of Integrated Traditional Chinese and Western Medicine, Binzhou Medical University, Yantai 264003, China