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\bibitem{Mao_etal2016} {\textquotedblleft}\textit{Realization of a tunable artificial atom at a supercritically charged vacancy in graphene}{\textquotedblright}. Mao J, Jiang Y, Moldovan D, Li G, Watanabe K, Taniguchi T, Masir MR, Peeters FM, Andrei EY, Nature physics \textbf{12}, 545 (2016).   http://doi.org/10.1038/nphys3665

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