[1] Firefox Focus: プライバシー保護ブラウザー - Google Play の Android アプリ ( ()) <https://play.google.com/store/apps/details?id=org.mozilla.focus>
[2] Introducing Firefox Focus - A Free, Fast Private Browser for iPhone - The Mozilla Blog ( ()) <https://blog.mozilla.org/blog/2016/11/17/introducing-firefox-focus-a-free-fast-and-easy-to-use-private-browser-for-ios/>
[3] 追跡広告をブロックするブラウザ「Firefox Focus」、Android版が登場 - CNET Japan ( ()) <https://japan.cnet.com/article/35103037/>
[4] Firefox Focus for Android Hits One Million Downloads! Today We’re Launching Three New User-Requested Features - The Mozilla Blog () <https://blog.mozilla.org/blog/2017/07/20/firefox-focus-android-hits-one-million-downloads-today-launching-three-new-user-requested-features/>