1. Face masks for the public during the covid-19 crisis
2. Association of Schools of Public Health in the European Region. Strategic use of masks as an element of a non-pharmaceutical measures set for a pandemic. 24 Apr 2020. https://www.aspher.org/download/412/strategic_use_of_masks_as_an_element_of_a_non-pharmaceutical_measures_set_for_a_pandemic.pdf
3. Centers for Disease Control and Prevention. Use of cloth face coverings to help slow the spread of covid-19. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html
4. Nuki P. Face masks: have we been asking the wrong question all along? Daily Telegraph 2020 Apr 16. https://www.telegraph.co.uk/global-health/science-and-disease/face-masks-asking-coronavirus/
5. Covid-19: four fifths of cases are asymptomatic, China figures indicate