Update README.md

README.md

@@ -127,5 +127,6 @@ Add references that you might have consulted for your methodology.
 - [The Anatomy of a 6-pager](https://writingcooperative.com/the-anatomy-of-an-amazon-6-pager-fc79f31a41c9) and an [example](https://docs.google.com/document/d/1LPh1LWx1z67YFo67DENYUGBaoKk39dtX7rWAeQHXzhg/edit) `Amazon`
 - [Writing for Distributed Teams](http://veekaybee.github.io/2021/07/17/p2s/), [How P2 Changed Automattic](https://ma.tt/2009/05/how-p2-changed-automattic/) `Automattic`
 - [Writing Technical Design Docs](https://medium.com/machine-words/writing-technical-design-docs-71f446e42f2e), [Writing Technical Design Docs, Revisited](https://medium.com/machine-words/writing-technical-design-docs-revisited-850d36570ec) `AWS`
+- [How to write a good software design doc](https://www.freecodecamp.org/news/how-to-write-a-good-software-design-document-66fcf019569c/) `Plaid`
 
 Contributions [welcome](https://github.com/eugeneyan/ml-design-docs/pulls)!