Norovirus outbreak in a school in the north of Portugal Castro, L and Cardoso, A I and Rebelo-Andrade, Helena and Gray, J J and Saraiva, Margarida and Gonçalves, G, Weekly releases (1997–2007), 8, 2424 (2004), https://doi.org/10.2807/esw.08.13.02424-en