Fatigue and symptom-based clusters in post COVID-19 patients: a multicentre, prospective, observational cohort study oleh Merel E. B. Cornelissen, Lizan D. Bloemsma, Anouk W. Vaes, Nadia Baalbaki, Qichen Deng, Rosanne J. H. C. G. Beijers, Lieke C. E. Noij, Laura Houweling, Somayeh Bazdar, Martijn A. Spruit, Anke H. Maitland-van der Zee, on behalf of the P4O2 Consortium