1. Center for Training and Research on Substance Use & HIV, Hanoi Medical University, Hanoi, Vietnam
2. David Geffen School of Medicine, University of California, Los Angeles, USA
3. School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
4. Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, Center for Community Health, University of California, Los Angeles, USA