diff --git a/doc/code-cells.ipynb b/doc/code-cells.ipynb
index 54bd2457..099a9efa 100644
--- a/doc/code-cells.ipynb
+++ b/doc/code-cells.ipynb
@@ -742,7 +742,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "The following code showing the 8 basic ANSI colors is based on https://tldp.org/HOWTO/Bash-Prompt-HOWTO/x329.html.\n",
+    "The following code showing the 8 basic ANSI colors is based on https://web.archive.org/web/20231225185739/https://tldp.org/HOWTO/Bash-Prompt-HOWTO/x329.html.\n",
     "Each of the 8 colors has an \"intense\" variation, which is used for bold text."
    ]
   },