1. World Health Organization. International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, 2nd edition. Geneva, Switzerland: World Health Organization; 2004. Available at: http://apps.who.int/classifications/apps/icd/icd10online/ (accessed November 2010).
2. Utah Department of Health, Center for Health Data Indicator-Based Information System for Public Health. Utah Death Certificate Database. 2010. Available at: http://ibis.health.utah.gov (accessed November 2010).
3. Opioid Analgesics and Rates of Fatal Drug Poisoning in the United States
4. Recent changes in drug poisoning mortality in the United States by urban-rural status and by drug type
5. Unintentional and undetermined poisoning deaths—11 states, 1990–2001;Centers for Disease Control and Prevention (CDC);MMWR Morb Mortal Wkly Rep,2004