1. Center for Behavioral Health Statistics and Quality. Behavioral health trends in the United States: Results from the 2014 National Survey on Drug Use and Health (HHS Publication No. SMA 15–4927, NSDUH Series H-50), 2015.
2. European Monitoring Centre for Drugs and Drug Addiction. Polydrug Use: Patterns and Responses. (2009). Luxembourg: Office for official publications of the European communities.
3. Mortality Following Inpatient Addictions Treatment