Update README.md

README.md

@@ -20,3 +20,4 @@ An [interactive mock-up app](https://design.penpot.app/#/view/441c1550-c424-11eb
 
 Similar projects:
 * [BabyBuddy](https://github.com/babybuddy/babybuddy), opensource webapp with a native [Android app](https://github.com/babybuddy/babybuddy-for-android) with multiple time trackers, very interesting implementation very similar to circalog, but can only specify what the timer was about at the end, not at the start. Also, graphs and stats are very limited since the goal is not to track sleep disorders. On the plus sides, the app supports being used by multiple different users in different locations since it runs online, and it has an awesome history feature that shows all changes that happened. For baby sleep tracking, it is a very good app, it just needs an export feature to display sleep graphs in other apps.
+* [Sleep Diary](https://sleepdiary.github.io/) by Andrew Sayers is a suite of tools and documentation to record and interpret sleep patterns. The tools are incredibly useful as they can convert between a variety of digital sleep diary formats and export clinical grade actigraphy-like graphs for grading by clinicians. The documentation is exhaustive and offers a methodology to discriminate sleep graphs into various circadian rhythm sleep disorders patterns. Circalog aim to implement a compatibility layer with these tools and also hopefully implement the methodology of Andrew Sayers to discriminate circadian rhythm disorders, alongside another novel unpublished method that will also be implemented too, the user will be able to choose.