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Frisch M, Melbye M.Frisch M, et al.Am J Epidemiol. 1995 May 15;141(10):916-22. doi: 10.1093/oxfordjournals.aje.a117358.Am J Epidemiol. 1995.PMID: 7741121
Frisch M, Olsen JH, Bautz A, Melbye M.Frisch M, et al.N Engl J Med. 1994 Aug 4;331(5):300-2. doi: 10.1056/NEJM199408043310504.N Engl J Med. 1994.PMID: 8022440Free article.