diff --git a/Aufgabe 3/aufgabe03.ipynb b/Aufgabe 3/aufgabe03.ipynb
index 12eb3c8..76992fd 100644
--- a/Aufgabe 3/aufgabe03.ipynb	
+++ b/Aufgabe 3/aufgabe03.ipynb	
@@ -140,6 +140,8 @@
    "outputs": [],
    "source": [
     "# Unit test to make sure neural net behaves as expected\n",
+    "# Uses example values from https://towardsdatascience.com/how-does-back-propagation-work-in-neural-networks-with-worked-example-bc59dfb97f48.\n",
+    "\n",
     "nn = NeuralNet(inputs=3, hidden_layers=[(4, sigmoid)])\n",
     "\n",
     "nn.weights = [\n",