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Falkingham PL, Gatesy SM.Falkingham PL, et al.Proc Natl Acad Sci U S A. 2014 Dec 23;111(51):18279-84. doi: 10.1073/pnas.1416252111. Epub 2014 Dec 8.Proc Natl Acad Sci U S A. 2014.PMID: 25489092Free PMC article.