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\usepackage[english]{babel}
\usepackage{fixltx2e}
\date{\today}
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\begin{document}



\subsubsection{\texorpdfstring{Single-layer MX2}{Singlelayer MX2}}
\label{sec:singlelayer_mx2}


Single-layer MX\textsubscript{2} blah blah...

\end{document}
