1. Centers for Disease Control and Prevention. Prescription drug overdose in the United States: Fact sheet. http://www.cdc.gov/homeandrecreationalsafety/overdose/facts.html . Updated 2014.
2. CDC grand rounds: prescription drug overdoses - a U.S. epidemic;Centers for Disease Control and Prevention (CDC);MMWR Morb Mortal Wkly Rep,2012
3. ‘Safe and effective when used as directed’: the case of chronic use of opioid analgesics;Ballantyne;JMed Toxicol,2012
4. Centers for Disease Control and Prevention (CDC). Drug overdose in the United States: Fact sheet. In: CDC—Facts—Drug Overdose—Home and Recreational Safety—Injury Center . 2012.
5. Increasing deaths from opioid analgesics in the United States