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Barber JR, Conner WE.Barber JR, et al. Among authors: conner we.Proc Natl Acad Sci U S A. 2007 May 29;104(22):9331-4. doi: 10.1073/pnas.0703627104. Epub 2007 May 21.Proc Natl Acad Sci U S A. 2007.PMID: 17517637Free PMC article.