Two masks can be better than one against COVID-19
Double masking and glove wearing: Is it necessary? - News
CDC: Double Masking Can Reduce COVID-19 Spread by up to 96.4%
Double masking: Which is better, two surgical masks or one N95?
Face Masks and Prevention of Respiratory Viral Infections: An Overview - Aerosol and Air Quality Research
Face mask use in the general population and optimal resource allocation during the COVID-19 pandemic
Wearing Two Masks Can Better Protect You From COVID-19
CDC: Double-masking helps reduce exposure to the coronavirus - POLITICO
Double Masking: How, Why, and When You Should Double Up on Face Masks - Enviro Safety Products Blog
COVID-19 Guidelines - Emergency Operations Center - County of Santa Clara
Carbon dioxide rises beyond acceptable safety levels in children under nose and mouth covering: Results of an experimental measurement study in healthy children - ScienceDirect
Lifting Universal Masking in Schools — Covid-19 Incidence among Students and Staff
Double masking to protect against COVID-19