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Simpson SJ, Despland E, Hägele BF, Dodgson T.Simpson SJ, et al.Proc Natl Acad Sci U S A. 2001 Mar 27;98(7):3895-7. doi: 10.1073/pnas.071527998.Proc Natl Acad Sci U S A. 2001.PMID: 11274411Free PMC article.