Mattiuzzi, Camilla, et al. “SARS-CoV-2 Recurrent RNA Positivity After Recovering from Coronavirus Disease 2019 (COVID-19): A Meta-Analysis”. Acta Biomedica Atenei Parmensis, vol. 91, no. 3, Sept. 2020, p. e2020014, https://doi.org/10.23750/abm.v91i3.10303.