1. EMCDDA (European Monitoring Centre for Drugs and Drug Addiction) European Drug Report 2016 Trends and Developments http://www.emcdda.europa.eu/edr2016
2. EMCDDA (European Monitoring Centre for Drugs and Drug Addiction) New psychoactive substances in Europe An update from the EU Early Warning System http://www.emcdda.europa.eu/publications/2015/new-psychoactive-substances
3. The new drug phenomenon;Brandt;Drug Test. Anal.,2014
4. UNODC (United Nations Office on Drug and Crime) https://www.unodc.org/documents/scientific/NPS_2013_SMART.pdf
5. Carroll County Health Department Alert Counterfeit Street Pills and fentanyl-Related Overdoses in Carroll County http://cchd.maryland.gov/alert-counterfeit-street-pills-and-fentanyl-related-overdoses-in-carroll-county/