1ICRF General Practice Research Group, ICRF Cancer Epidemiology Unit, University of Oxford, Oxford, UK
3Department of Public Health, University of Helsinki, Helsinki, Finland
4Medical Follow-up Agency, Institute of Medicine, National Academy of Sciences, Washington, DC, USA
5Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden
6Danish Twin Registry & Epidemiology, Institute of Public Health
7Danish Centre for Demographic Research, University of Southern Denmark, Odense, Denmark
Copyright © 2000 Cancer Research Campaign
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