1. National Hospital Ambulatory Medical Care Survey: 2003 Emergency Department Summary: Advance Data from Vital and Health Statistics; No. 358;McCaig,2005
2. Emergency Room Diversions;Brewster,2001
3. Plan and Operation of the National Hospital Ambulatory Medical Care Survey;McCaig,1994
4. A Reason for Visit Classification for Ambulatory Care;Schneider,1979
5. International Classification of Diseases, Ninth Revision, Clinical Modification,1998