Chavez-Ruiz, M. et al. 2021. Methodology for evaluating the level of respiratory protection of masks and respirators against particles similar to those that transmit SARS-CoV-2. Revista Peruana de Medicina Experimental y Salud Pública. 38, 3 (Sep. 2021), 391–8. DOI:https://doi.org/10.17843/rpmesp.2021.383.8036.