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Olsson H, Poom L.Olsson H, et al.Proc Natl Acad Sci U S A. 2005 Jun 14;102(24):8776-80. doi: 10.1073/pnas.0500810102. Epub 2005 Jun 3.Proc Natl Acad Sci U S A. 2005.PMID: 15937119Free PMC article.