Affiliation: | 1. National Institutes of Health, National Cancer Institute, Division of Cancer Epidemiology and Genetics, Biostatistics Branch, 9609 Medical Center Drive, MSC 9776, Bethesda, MD 20892, U.S.A.;2. McGill University Department of Mathematics and Statistics, Burnside Hall Room 1005, 805 Sherbrooke Street West, Montreal Quebec, Canada H3A 0B9 |