1. School of Management, Beijing University of Chinese Medicine, Beijing, China
2. Institute of Medical Information, Chinese Academy of Medical Sciences, Beijing, China
3. Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
4. Institute of Epidemiology and Health Care, University College London, London, UK
5. Peking University Medical library, Beijing, China
6. School of Economics and Management, Beijing Jiaotong University, Beijing, China
7. National Institute of Chinese Medicine Development and Strategy, Beijing University of Chinese Medicine, Beijing, China.