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Zangerl AR, Berenbaum MR.Zangerl AR, et al.Proc Natl Acad Sci U S A. 2005 Oct 25;102(43):15529-32. doi: 10.1073/pnas.0507805102. Epub 2005 Oct 17.Proc Natl Acad Sci U S A. 2005.PMID: 16230607Free PMC article.