diff --git a/README.md b/README.md
index 5acaf6d..895952c 100644
--- a/README.md
+++ b/README.md
@@ -13,3 +13,9 @@
 
 * [MIT license](LICENSE.txt)
 
+## External library
+
+* [hayashi.jar](https://osdn.net/projects/hayashilib/releases/)
+* javax.json.jar
+* [commons-compress-1.18.jar](https://commons.apache.org/proper/commons-compress/download_compress.cgi) - Apache Commons Compress
+* [hsqldb.jar](http://hsqldb.org/) - HSQLDB