TI - BEijing, china PT - JOUR DP - 2011 TA - Archives of Internal Medicine pages = {1774}, VI - 171 IP - 19 AID - 10.1001/archinternmed.2011.491 [doi] 4100 - http://dx.doi.org/10.1001/archinternmed.2011.491 SO - Archives of Internal Medicine October 24, 2011 171(19):1774