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Ewers A, Nestler N, Pogatzki-Zahn E, Bauer Z, Richter H, Osterbrink J.Ewers A, et al.Schmerz. 2011 Sep;25(5):516-21. doi: 10.1007/s00482-011-1089-1.Schmerz. 2011.PMID: 21909743German.