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Bringhurst RM, Cardon ZG, Gage DJ.Bringhurst RM, et al.Proc Natl Acad Sci U S A. 2001 Apr 10;98(8):4540-5. doi: 10.1073/pnas.071375898. Epub 2001 Mar 27.Proc Natl Acad Sci U S A. 2001.PMID: 11274355Free PMC article.