https://tools.ietf.org/html/rfc6749

https://openid.net/foundation/ particularly https://openid.net/connect/

https://en.wikipedia.org/wiki/OpenID

https://en.wikipedia.org/wiki/OpenID_Connect

http://www.passportjs.org/docs/authenticate/

Net Ninja's OAuth with Passport

https://developer.okta.com/blog/2018/05/18/node-authentication-with-passport-and-oidc. Uses the familiar Express architecture we consider best practice.

https://auth0.com/blog/from-theory-to-practice-adding-two-factor-to-node-dot-js/