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Spitzer B, Blankenburg F.Spitzer B, et al. Among authors: blankenburg f.Proc Natl Acad Sci U S A. 2011 May 17;108(20):8444-9. doi: 10.1073/pnas.1104189108. Epub 2011 May 2.Proc Natl Acad Sci U S A. 2011.PMID: 21536865Free PMC article.