1. Radiation Epidemiology Branch, National Cancer Institute, Bethesda, Maryland 20892-9778
2. Centre for Occupational and Environmental Health, Faculty of Biology, Medicine and Health, The University of Manchester, Ellen Wilkinson Building, Oxford Road, Manchester M13 9PL, United Kingdom
3. Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, OX11 0RQ United Kingdom
4. Retired, formerly with the Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom