Asad Hafeez, M. Hashmi, N. Ahmad, S. Hashmi, and T. . Ismail. “Association Between ABO Blood Groups and Clinical Characteristics, Severity, and Outcomes of COVID-19 Patients”. Pakistan Journal of Chest Medicine, vol. 32, no. 1, Mar. 2026, pp. 33-39, https://pjcm.net/index.php/pjcm/article/view/1117.