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Franks PJ, Beerling DJ.Franks PJ, et al. Among authors: beerling dj.Proc Natl Acad Sci U S A. 2009 Jun 23;106(25):10343-7. doi: 10.1073/pnas.0904209106. Epub 2009 Jun 8.Proc Natl Acad Sci U S A. 2009.PMID: 19506250Free PMC article.