diff --git a/README.md b/README.md
index 5a2642f..dbb7ddc 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ A Scheme-like typesetting LISP interpreter and editor that using SILE typesettin
 ![圖片](https://user-images.githubusercontent.com/184107/122680547-47c8e000-d222-11eb-8ac3-be02df28e4b0.png)
 
 ## License
-GPLv3
+GPLv3 (except those inside `thirdparty/`)
 
 ## Dependencies
 * Python3