Centers for Disease Control and Prevention (U.S.). CDC Mask Order Remains in Effect and CDC Realigns Travel Health Notice System : CDC Media Statement, April 13, 2022,
Centers for Disease Control and Prevention : Documents Relating to the COVID-19 Pandemic.
https://fraser.stlouisfed.org/archival/6318/item/615308/content/pdf/20220413_cdc_maskExtension, accessed on June 9, 2026.