Add license note

notebooks/matrix_matrix.ipynb

@@ -1108,6 +1108,26 @@
     "println(\"Optimal speedup = \", P)\n",
     "println(\"Efficiency = \", 100*(T1/TP)/P, \"%\")"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "8e171362",
+   "metadata": {},
+   "source": [
+    "# License\n",
+    "\n",
+    "TODO: replace link to website\n",
+    "\n",
+    "This notebook is part of the course [Programming Large Scale Parallel Systems](http://localhost:8000/) at Vrije Universiteit Amsterdam and may be used under a [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/) license."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "86b7b044",
+   "metadata": {},
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {