2FA via Authenticator - Now Fully Rolled Out! - Announcements

How two-factor authentication can protect you from account hacks

Twitter Two-Factor Authentication: Twitter to no longer support two-factor authentication for free users - The Economic Times

Two-Factor Authentication - Blog - Method Grid

Twitter two-factor authentication via 2FA apps and hardware tokens, by Protectimus, The Startup

2FA explained: How to enable it and how it works

Twitter now allows two-factor authentication via third-party apps

Twitter's two-factor authentication moves behind paywall effective today

Facebook Is Beefing Up Its Two-Factor Authentication

Researchers warn against Google Authenticator feature - Android Authority

How do I set up two factor authentication (2FA)? – Blockchain Support Center