Squeri, Raffaele, et al. “Healthcare workers’ Vaccination at European and Italian Level: A Narrative Review: Updates of Vaccination Coverages of HCWs”. Acta Biomedica Atenei Parmensis, vol. 90, no. 9-S, Sept. 2019, pp. 45-53, https://doi.org/10.23750/abm.v90i9-S.8703.