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Royston P, Altman DG.Royston P, et al. Among authors: altman dg.BMC Med Res Methodol. 2013 Mar 6;13:33. doi: 10.1186/1471-2288-13-33.BMC Med Res Methodol. 2013.PMID: 23496923Free PMC article.
Burton A, Altman DG, Royston P, Holder RL.Burton A, et al. Among authors: altman dg.Stat Med. 2006 Dec 30;25(24):4279-92. doi: 10.1002/sim.2673.Stat Med. 2006.PMID: 16947139