1. European Monitoring Centre for Drugs and Drug Addiction (2012) The State of the Drugs Problem in Europe, Annual Report, Lisbon, Portugal. http://www.emcdda.europa.eu/publications/annual-report/2012 . Accessed 30 Apr 2013
2. European Monitoring Centre for Drugs and Drug Addiction, and Europol (joint publication) (2013) EU Drug Markets Report: a Strategic Analysis, Lisbon, Portugal; The Hague, The Netherlands. http://www.emcdda.europa.eu/publications/joint-publications/drug-markets . Accessed 30 Apr 2013
3. Meyer MR, Maurer HH (2010) Curr Drug Metab 11:468–482
4. Maurer HH (2010) Ther Drug Monit 32:544–549
5. Staack RF, Maurer HM (2005) Curr Drug Metab 6:259–274