1. Pharmaceutical Overdose Deaths, United States, 2010
2. Vital signs: Overdoses of prescription opioid pain relievers—United States, 1999–2008;Centers for Disease Control and Prevention;MMWR Morb Mortal Wkly Rep,2011
3. SAMHSA Opioid Overdose Prevention Toolkit: Information for Prescribers. Rockville, MD: Substance Abuse and Mental Health Services Administration, 2013. HHS Publication No. (SMA) 13-4742.
4. Risk Factors for Opioid-Induced Excessive Respiratory Depression
5. Stephens E Louden M VanDe Voort J Opioid Toxicity: Medscape. 2012. Available at: http://emedicine.medscape.com/article/815784-overview (accessed December 2013); updated October 23, 2012, accessed December 8 2013.