diff --git a/README.md b/README.md
index f276d9f..16e42fe 100644
--- a/README.md
+++ b/README.md
@@ -38,4 +38,7 @@ npm run parse
 ```
 
 ## License
-MIT
+This software is released under the [MIT License](LICENSE).
+
+This software includes codes of other softwares:
+- PEG.js: https://raw.githubusercontent.com/pegjs/pegjs/master/LICENSE