2022
https://auth0.com/blog/complete-guide-to-angular-user-authentication/
https://auth0.com/blog/complete-guide-to-angular-user-authentication/
2021
https://medium.com/@christophergsell/incorporating-auth0-with-a-firebase-backend-8cf042f4670
2018
https://auth0.com/blog/developing-real-time-apps-with-firebase-and-firestore/