1. UNODC. World Drug Report 2013. United Nations Office of Drugs and Crime (UNODC), United Nations publication, Sales No E13XI6, 2013.
2. UNODC. The Challenge of New Psychoactive Substances. United Nations Office of Drugs and Crime (UNODC), A Report from the Global SMART Programme, March 2013.
3. A brief history of ‘new psychoactive substances’;King;Drug Test Anal,2011
4. I. Sample ‘Superman’ pill deaths spark calls for dangerous-drugs alert system. The Guardian 17 January 2015. Available at: http://wwwtheguardiancom/society/2015/jan/16/superman-pill-deaths-dangerous-drugs-alert-system [accessed 26 February 2015].
5. D. Nutt The Superman pill deaths are the result of our illogical drugs policy The Guardian 5 January 2015. Available at: http://wwwtheguardiancom/commentisfree/2015/jan/05/superman-pill-ecstasy-pma-deaths-drugs-policy [accessed 26 February 2015].