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Friesner RA.Friesner RA.Proc Natl Acad Sci U S A. 2005 May 10;102(19):6648-53. doi: 10.1073/pnas.0408036102. Epub 2005 May 3.Proc Natl Acad Sci U S A. 2005.PMID: 15870212Free PMC article.