Enhanced epidemiological surveillance of influenza A(H1N1)v in Italy Rizzo, C and Declich, S and Bella, A and Caporali, M G and Lana, S and Pompa, M G and Vellucci, L and Salmaso, S, Eurosurveillance, 14, 19266 (2009), https://doi.org/10.2807/ese.14.27.19266-en