Fact check: Masks are effective against COVID-19; OSHA doesn't say they offer no protection
Mask Mandate: San Francisco Bay Area health officials issue indoor mask mandate, regardless of vaccination status - ABC7 San Francisco
Face masks during the COVID-19 pandemic - SciLine
Use and Care of Masks
Face Masks in Child Care Programs California Childcare Health Program
When and Why to Wear a Mask
The science and psychology behind masking to prevent the spread of COVID-19
Juntos, We Can Stop COVID-19! - Salud America
Face Masks for Illness
Still Confused About Masks? Here's the Science Behind How Face Masks Prevent Coronavirus
How to Put on and Remove a Face Mask - Disease Prevention and Control, San Francisco Department of Public Health