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\bibitem{Silva_etal2015} {\textquotedblleft}\textit{Elemental composition of PM$_{2.5}$ in Araraquara City (Southeast Brazil) during seasons with and without sugar cane burning}{\textquotedblright}. Silva FS, Godoi RHM, Tauler R, de Andr{\'e} PA, Saldiva PHN, Van Grieken R, de Marchi MRR, Journal of environmental protection \textbf{6}, 426 (2015).   http://doi.org/10.4236/JEP.2015.65041

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