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Forman D, Vincent TJ, Doll R.Forman D, et al.Br Med J (Clin Res Ed). 1986 May 24;292(6532):1357-61. doi: 10.1136/bmj.292.6532.1357.Br Med J (Clin Res Ed). 1986.PMID: 3011186Free PMC article.