Umair, R., Y. Shadma, S. Areena, H. ., V. MK, V. P, A. J, and S. VK. “Personal Protective Equipments Preventing Transmission of COVID-19, Crisis Capacity Strategies and Continued Preparedness: A Systematic Review”. International Journal of Health and Clinical Research, vol. 4, no. 3, Feb. 2021, pp. 252-6, https://ijhcr.com/index.php/ijhcr/article/view/885.