diff --git a/tools.md b/tools.md
index cc1ebf3..be6806e 100644
--- a/tools.md
+++ b/tools.md
@@ -26,6 +26,7 @@
   * Matplotlib
     * [book of examples](https://raw.githubusercontent.com/rougier/scientific-visualization-book/master/pdf/book.pdf)
     * [cheatsheets](https://matplotlib.org/cheatsheets/)
+  * [d3.js example](http://www.r2d3.us/visual-intro-to-machine-learning-part-2/)
 * **API**
   * JSON API is the easiet API - [follow the rules](https://jsonapi.org/format/#)
   * Requesting - use Python-[requests](https://docs.python-requests.org/en/latest/)