1. Warner M Chen L Makuc D . NCHS data brief: increase in fatal poisonings involving opioid analgesics in the United States, 1999–2006 (September 2009). www.cdc.gov/nchs/data/databriefs/db22.htm (accessed 2013 Sep 3).
2. Warner M Chen LH Makuc DM . NCHS data brief: drug poisoning deaths in the United States, 1980–2008 (December 2011). www.cdc.gov/nchs/data/databriefs/db81.pdf (accessed 2013 Sep 3).
3. QuickStats: number of deaths from poisoning, drug poisoning, and drug poisoning involving opioid analgesics—United States, 1999–2010;Centers for Disease Control and Prevention;MMWR Morb Mortal Wkly Rep,2013
4. Substance Abuse and Mental Health Services Administration. Results from the 2009 National Survey on Drug Use and Health: volume I: summary of national findings (September 2010). www.samhsa.gov/data/2k9/2k9Resultsweb/web/2k9results.pdf (accessed 2013 Sep 3).
5. Substance Abuse and Mental Health Services Administration. The DAWN report: highlights of the 2009 Drug Abuse Warning Network (DAWN) findings on drug-related emergency department visits (December 28, 2010). http://oas.samhsa.gov/2k10/DAWN034/EDHighlights.htm (accessed 2013 Sep 3).