1. Drug Policy Modelling Program, National Drug and Alcohol Research Centre, UNSW Australia, Sydney, NSW, Australia
2. National Drug Research Institute, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
3. Behaviours and Health Risks Program, Burnet Institute, Melbourne, VIC, Australia
4. Institute for Social Science Research, The University of Queensland, St Lucia, QLD, Australia
5. Department of Population Health, NYU Langone Medical Center, New York, NY, USA
6. Center for Drug Use and HIV Research, NYU Rory Meyers College of Nursing, New York, NY, USA
7. University of Zurich, Zurich, Switzerland
8. Institute of Epidemiology & Health Care, Faculty of Population Health Sciences, University College London
9. Global Drug Survey Ltd, London, UK