1. Department of Hepatobiliary Surgery, First Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China.
2. The Institute for Global Health Policy Research, Bureau of International Health Cooperation, National Center for Global Health and Medicine, Tokyo, Japan.
3. Department of Hepatobiliary Surgery, Qinghai Red Cross Hospital, Xining, China.
4. Department of General Surgery, Shanxian Central Hospital, Heze, China.