Toori, Kaleem Ullah, Muhammad Arsalan Qureshi, and Asma Chaudhry. “Lymphopenia: A Useful Predictor of COVID-19 Disease Severity and Mortality”. Pakistan Journal of Medical Sciences 37, no. 7 (October 6, 2021). Accessed April 19, 2024. https://www.pjms.org.pk/index.php/pjms/article/view/4085.