<https://www.linuxfoundation.jp/blog/2021/06/adoption-of-a-covid-19-vaccine-required-approach-for-our-fall-2021-event-line-up/#article>
<http://schema.org/headline>
"今秋米国・EUで開催される対面イベントへの参加には COVID-19ワクチン接種証明が必要に ー Linux Foundation Event"
<https://www.linuxfoundation.jp/blog/2021/06/adoption-of-a-covid-19-vaccine-required-approach-for-our-fall-2021-event-line-up/>