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Harron K, Wade A, Gilbert R, Muller-Pebody B, Goldstein H.Harron K, et al.BMC Med Res Methodol. 2014 Mar 5;14:36. doi: 10.1186/1471-2288-14-36.BMC Med Res Methodol. 2014.PMID: 24597489Free PMC article.