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\bibitem{Hens_etal2012} {\textquotedblleft}\textit{Producing photoluminescent species from Sp$^{2}$ carbons}{\textquotedblright}. Hens SC, Shenderova O, Turner S, Fullerenes, nanotubes, and carbon nanostructures \textbf{20}, 502 (2012).   http://doi.org/10.1080/1536383X.2012.655667

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