Youtube - Cássio Botaro:

https://www.youtube.com/cassiobotaro

Companies that use RFCs or Design Docs:

https://blog.pragmaticengineer.com/rfcs-and-design-docs/

How to write an effective design document:

https://rinaarts.com/how-to-write-an-effective-design-document/

Uma introdução aos Design Docs:

https://medium.com/inside-picpay/uma-introdu%C3%A7%C3%A3o-aos-design-docs-8590f28f4cc1

Design Docs at Google:

https://www.industrialempathy.com/posts/design-docs-at-google/