1. UK Centre for Tobacco Control Studies University of Nottingham Division of Epidemiology and Public Health Nottingham UK
2. UK Centre for Tobacco Control Studies National Addiction Centre Institute of Psychiatry King's College London Addiction Sciences Building London UK
3. Division of General Medicine Brigham and Women's Hospital Department of Health Care Policy Harvard Medical School Boston MA USA
4. Harvard Medical School Boston MA USA
5. Tobacco Research and Treatment Centre General Medicine Division Massachusetts General Hospital Boston MA USA