Human immunodeficiency virus among people who inject drugs: Is risk increasing in Europe? Hedrich, D and Kalamara, E and Sfetcu, O and Pharris, A and Noor, A and Wiessing, L and Hope, V and Van de Laar , M, Eurosurveillance, 18, 20648 (2013), https://doi.org/10.2807/1560-7917.ES2013.18.48.20648