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Crawford F, Hart R, Bell-Syer SE, Torgerson DJ, Young P, Russell I.Crawford F, et al. Among authors: torgerson dj.BMJ. 2001 Feb 3;322(7281):288-9. doi: 10.1136/bmj.322.7281.288.BMJ. 2001.PMID: 11157535Free PMC article.