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Gramlich OW, Beck S, von Thun Und Hohenstein-Blaul N, Boehm N, Ziegler A, Vetter JM, Pfeiffer N, Grus FH.Gramlich OW, et al. Among authors: vetter jm.PLoS One. 2013;8(2):e57557. doi: 10.1371/journal.pone.0057557. Epub 2013 Feb 25.PLoS One. 2013.PMID: 23451242Free PMC article.