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López-García P, Philippe H, Gail F, Moreira D.López-García P, et al.Proc Natl Acad Sci U S A. 2003 Jan 21;100(2):697-702. doi: 10.1073/pnas.0235779100. Epub 2003 Jan 9.Proc Natl Acad Sci U S A. 2003.PMID: 12522264Free PMC article.