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Schmidt M, Maeng M, Jakobsen CJ, Madsen M, Thuesen L, Nielsen PH, Bøtker HE, Sørensen HT.Schmidt M, et al.Clin Epidemiol. 2010 Aug 9;2:137-44. doi: 10.2147/clep.s10190.Clin Epidemiol. 2010.PMID: 20865111Free PMC article.