Protocol COVID-19 Surveillance in residential institutions - version 5.2, Dequeker, Sara, Latour Katrien, Islamaj Esma, Int Panis Laura, Callies Milena, Catteau Lucy, Catry Boudewijn, Bustos Sierra Natalia, Renard Françoise, and Vandael Eline , 02/07/2021, Brussels, Belgium, p.17, (2021)