1. Graff LG (2009) Observation medicine: The healthcare system's tincture of time. American College of Emergency Physicians online publication. 176. Available at: http://www.acep.org/WorkArea/DownloadAsset.aspx?id=45885. Accessed November 11, 2009
2. Farkouh ME, Smars PA, Reeder GS et al (1998) A clinical trial of a chest-pain observation unit for patients with unstable angina. Chest pain evaluation in the emergency room (CHEER) investigators. N Engl J Med 339:1882–1888
3. Kohn LT, Corrigan JM, Donaldson MS (Institute of Medicine) (2000). To err is human: building a safer health system. National Academy Press, Washington, DC
4. Brennan TA, Leape LL, Laird NM et al (1991) Incidence of adverse events and negligence in hospitalized patients. Results of the Harvard Medical Practice Study I. N Engl J Med 324:370–376
5. Fisher ES, Wennberg JE, Stukel TA et al (2000) Associations among hospital capacity, utilization, and mortality of US Medicare beneficiaries, controlling for sociodemographic factors. Health Serv Res 34:1351–1362