Osuna, A. (2006) “Community-Acquired Pneumonia and Pneumonia Severity Index 20 (PSI-20): a study of 262 patients”, Portuguese Journal Internal Medicine. Lisboa, Portugal, 13(3), pp. 162–171. Available at: https://revista.spmi.pt/index.php/rpmi/article/view/1641 (Accessed: 17 June 2026).