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Hansen JD, Landis ED, Phillips RB.Hansen JD, et al. Among authors: landis ed.Proc Natl Acad Sci U S A. 2005 May 10;102(19):6919-24. doi: 10.1073/pnas.0500027102. Epub 2005 Apr 29.Proc Natl Acad Sci U S A. 2005.PMID: 15863615Free PMC article.