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\bibitem{vanWalsem_etal2018} {\textquotedblleft}\textit{Integration of a photocatalytic multi-tube reactor for indoor air purification in HVAC systems : a feasibility study}{\textquotedblright}. van Walsem J, Roegiers J, Modde B, Lenaerts S, Denys S, Environmental Science and Pollution Research \textbf{25}, 18015 (2018).   http://doi.org/10.1007/S11356-018-2017-Z

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