edit README and add links to other python packages

README.md

@@ -48,12 +48,10 @@ card = Card()
 Choose a rating and review the card
 
 ```python
-"""
-Rating.Again # (==0) forgot the card
-Rating.Hard # (==1) remembered the card, but with serious difficulty
-Rating.Good # (==2) remembered the card after a hesitation
-Rating.Easy # (==3) remembered the card easily
-"""
+# Rating.Again (==1) forgot the card
+# Rating.Hard (==2) remembered the card with serious difficulty
+# Rating.Good (==3) remembered the card after a hesitation
+# Rating.Easy (==4) remembered the card easily
 
 rating = Rating.Good
 
@@ -123,6 +121,12 @@ This python package is currently unstable and adheres to the following versionin
 
 Once this package is considered stable, the **Major** version will be bumped to 1.0.0 and will follow [semver](https://semver.org/).
 
+## Other SRS python packages
+
+- [FSRS](https://github.com/open-spaced-repetition/py-fsrs)
+- [SM-2](https://github.com/open-spaced-repetition/sm-2)
+- [Leitner System](https://github.com/open-spaced-repetition/leitner-box)
+
 ## Contribute
 
 Checkout [CONTRIBUTING](https://github.com/open-spaced-repetition/anki-sm-2/blob/main/CONTRIBUTING.md) to help improve Anki SM-2!