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\bibitem{VanGrieken_etal1991} {\textquotedblleft}\textit{Current trends in the literature on X-ray emission spectrometry}{\textquotedblright}. Van Grieken R, Markowicz A, Veny P, X-ray spectrometry \textbf{20}, 271 (1991).   http://doi.org/10.1002/XRS.1300200605

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