1. Frequent overcrowding in U.S. Emergency Departments;Derlet;Acad Emerg Med,2001
2. If you want to fix crowding, start by fixing your hospital;Asplin;Ann Emerg Med,2007
3. American hospital association hospital statistics;Chicago,1999
4. Trends in hospital emergency department utilization. United States 1992–99;Burt;Vital Health Stat,2001
5. National hospital ambulatory medical care survey. 2006 emergency department summary;Pitts;Natl Health Stat Report,2008