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\bibitem{Sozen_etal2021} {\textquotedblleft}\textit{Vibrational and optical identification of GeO$_{2}$ and GeO single layers : a first-principles study}{\textquotedblright}. Sozen Y, Yagmurcukardes M, Sahin H, Physical Chemistry Chemical Physics \textbf{23}, 21307 (2021).   http://doi.org/10.1039/D1CP02299G

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