Charu Mishra, Arvind Kumar, Yogesh Kumar Yadav, and Vijay Kumar. “Causatum in Adults up till 6 Months After COVID-19 Infection: A Longitudinal Study”. International Journal of Health and Clinical Research, vol. 4, no. 15, Aug. 2021, pp. 352-7, https://www.ijhcr.com/index.php/ijhcr/article/view/2529.