Bai, Kavita, Ramesh Kumar, Urooj Bhatti, Keenjhar Rani, and Mumtaz Ali Memon. “Association of Headache and Other Attributes to Duration of Wearing Face Mask During Pandemic COVID -19”. Pakistan Journal of Physiology 17, no. 1 (March 31, 2021): 26–29. Accessed April 26, 2024. https://pjp.pps.org.pk/index.php/PJP/article/view/1293.