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\bibitem{Xu_etal2009} {\textquotedblleft}\textit{Dependence of resistivity on electron density and temperature in graphene}{\textquotedblright}. Xu W, Peeters FM, Lu TC, Physical review : B : solid state \textbf{79}, 073403 (2009).   http://doi.org/10.1103/PhysRevB.79.073403

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