Singh, Abhishek, Kapil Dev Soni, Yudhyavir Singh, Richa Aggarwal, Vineeta Venkateswaran, Mohd Suhail Ashar, and Anjan Trikha. “Alveolar Arterial Gradient and Respiratory Index in Predicting the Outcome of COVID-19 Patients; A Retrospective Cross-Sectional Study”. Archives of Academic Emergency Medicine 10, no. 1 (April 14, 2022): e28. Accessed July 8, 2026. https://journals.sbmu.ac.ir/aaem/index.php/AAEM/article/view/1543.