Osman, Baderin, et al. “Respiratory Protective Equipment (RPE) Standard – Disposable Filtering Half Mask on N95, FFP2 and KN95”. Journal of Advanced Industrial Technology and Application, vol. 3, no. 1, June 2022, pp. 50-54, https://publisher.uthm.edu.my/ojs/index.php/jaita/article/view/11366.