In den USA wurden mask exemption cards von der Organisation "Freedom to Breathe Agency" verteilt.<ref>https://quackwatch.org/consumer-protection/mask-exemption-cards-are-not-government-supported/</ref> | In den USA wurden mask exemption cards von der Organisation "Freedom to Breathe Agency" verteilt.<ref>https://quackwatch.org/consumer-protection/mask-exemption-cards-are-not-government-supported/</ref> |