1. IrisZorg, Institute for Addiction Care, Sheltered Housing and Social Support Services, Arnhem, The Netherlands
2. Nijmegen Institute for Scientist-Practitioners in Addiction (NISPA), Radboud University Nijmegen/ACSW, The Netherlands
3. Behavioural Science Institute, Radboud University Nijmegen, The Netherlands
4. Novadic-Kentron, Centre for Addiction Care, Vught, The Netherlands