References Authors Steinle, S. Sleeuwenhoek, A. Mueller, W. Horwell, C. J. Apsley, A. Davis, A. Cherrie, J. W. Galea, K. S. Category Respiratory protection Sub-Category PPE testing Year 2018 Publication International Journal of Hygiene and Environmental Health Volume, Issue, Pages 221(6): 977-984 DOI 10.1016/j.ijheh.2018.03.011 URL https://www.sciencedirect.com/science/article/pii/S1438463917308027?via%3Dihub=