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Gebregziabher M, Egede L, Gilbert GE, Hunt K, Nietert PJ, Mauldin P.Gebregziabher M, et al. Among authors: nietert pj.BMC Med Res Methodol. 2012 Oct 24;12:163. doi: 10.1186/1471-2288-12-163.BMC Med Res Methodol. 2012.PMID: 23095325Free PMC article.