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Hahn ME, Karchner SI, Shapiro MA, Perera SA.Hahn ME, et al. Among authors: karchner si.Proc Natl Acad Sci U S A. 1997 Dec 9;94(25):13743-8. doi: 10.1073/pnas.94.25.13743.Proc Natl Acad Sci U S A. 1997.PMID: 9391097Free PMC article.