diff --git a/content/labs/visualization/2020-06-13-different-types-of-graphs.md b/content/labs/visualization/2020-06-13-different-types-of-graphs.md
index 9b88ccd..57bb6ee 100644
--- a/content/labs/visualization/2020-06-13-different-types-of-graphs.md
+++ b/content/labs/visualization/2020-06-13-different-types-of-graphs.md
@@ -288,3 +288,6 @@ chart=true
   });
 {{< /chart >}}
 
+
+## 参考
+- [Chart.jsでグラフを描画してみた - Qiita](https://qiita.com/Haruka-Ogawa/items/59facd24f2a8bdb6d369#3-2-%E6%A3%92%E3%82%B0%E3%83%A9%E3%83%95)