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\bibitem{Mishra_etal2012} {\textquotedblleft}\textit{Wintertime spatio-temporal variation of ultrafine particles in a Belgian city}{\textquotedblright}. Mishra VK, Kumar P, Van Poppel M, Bleux N, Frijns E, Reggente M, Berghmans P, Int Panis L, Samson R, The science of the total environment \textbf{431}, 307 (2012).   http://doi.org/10.1016/J.SCITOTENV.2012.05.054

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