Jianshe , Yang, and Kang Li. “Risk Stratification of Patients Admitted to Hospital With Covid-19 Using the ISARIC WHO Clinical Characterisation Protocol: Development and Validation of the 4C Mortality Score”. Diagnostic and Treatment Advances in COVID-19 and SARS-CoV-2 (February 9, 2023): 250–252. Accessed June 13, 2026. https://stm.bookpi.org/DTACSC/article/view/9572.