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Welthagen W, Schnelle-Kreis J, Zimmermann R.Welthagen W, et al. Among authors: zimmermann r.J Chromatogr A. 2003 Nov 26;1019(1-2):233-49. doi: 10.1016/j.chroma.2003.08.053.J Chromatogr A. 2003.PMID: 14650618