1. Department of Epidemiology, Hiroshima and Nagasaki, Japan
2. Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland
3. Visiting Researcher, Radiation Effects Research Foundation, Hiroshima and Nagasaki, Japan
4. Department of Statistics, Hiroshima and Nagasaki, Japan
5. Hirosoft International Corporation, Eureka, California