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