Burden of COVID-19 on primary care in Belgium: a prospective nationwide observational study from March to August 2020, Vaes, Bert, Vos Bénédicte, Foidart Maxime, De Schreye Robrecht, Schrans Diëgo, Philips Hilde, Aertgeerts Bert, and Doggen Kris , Archives of Public Health, Volume 80, Issue 1, (2022)