Beretta, Ottavio, Simona Casati Pagani, Mario Lazzaro, Giorgio Merlani, and Martine Bouvier Gallacchi. “Seroprevalence of the SARS-CoV-2 Virus in the Population of the Southern Switzerland (Canton Ticino) – Cohort Study, Results at 12 months”. Swiss Medical Weekly 151, no. 5152 (December 28, 2021): w30116. Accessed July 16, 2024. https://smw.ch/index.php/smw/article/view/3135.