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Laeng B, Endestad T.Laeng B, et al.Proc Natl Acad Sci U S A. 2012 Feb 7;109(6):2162-7. doi: 10.1073/pnas.1118298109. Epub 2012 Jan 23.Proc Natl Acad Sci U S A. 2012.PMID: 22308422Free PMC article.