diff --git a/book/features/plotly.ipynb b/book/features/plotly.ipynb
index 08005fc..0f0a451 100644
--- a/book/features/plotly.ipynb
+++ b/book/features/plotly.ipynb
@@ -487,7 +487,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Eventually in combination with [](../_git/github.com_TeachBooks_Sphinx-NB-Execution-Patterns/Manual/README.html)"
+    "Eventually in combination with [](../_git/github.com_TeachBooks_Sphinx-NB-Execution-Patterns/Manual/README.md)"
    ]
   }
  ],