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Gil GS, Morikava FS, Santin GC, Pintarelli TP, Fraiz FC, Ferreira FM.Gil GS, et al. Among authors: fraiz fc.BMC Med Res Methodol. 2015 Mar 8;15:14. doi: 10.1186/s12874-015-0002-5.BMC Med Res Methodol. 2015.PMID: 25887179Free PMC article.