SAML:

https://developers.onelogin.com/saml

https://stackoverflow.com/questions/26901368/saml-adfs-node-js-implementation-guide/36897549#36897549

Oauth:

https://stormpath.com/blog/what-the-heck-is-oauth

http://blog.scottlogic.com/2015/11/19/oauth2-with-saml2.html

https://stackoverflow.com/questions/43291638/single-sign-on-authentication-vs-authorization

SAML vs Oauth2 for SSO strategy:

https://www.mutuallyhuman.com/blog/2013/05/09/choosing-an-sso-strategy-saml-vs-oauth2/

Oauth for SSO:

https://blog.heroku.com/oauth-sso