diff --git a/ml1/2_5_1_kNN_Model.ipynb b/ml1/2_5_1_kNN_Model.ipynb
index bd0fcce..15eeefd 100644
--- a/ml1/2_5_1_kNN_Model.ipynb
+++ b/ml1/2_5_1_kNN_Model.ipynb
@@ -379,8 +379,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "* [KNeighborsClassifier API scikit-learn](http://scikit-learn.org/stable/modules/generated/sklearn.neighbors.KNeighborsClassifier.html)\n",
-    "* [Learning scikit-learn: Machine Learning in Python](https://learning.oreilly.com/library/view/scikit-learn-machine/9781788833479/), Raúl Garreta; Guillermo Moncecchi, Packt Publishing, 2013.\n"
+    "* [KNeighborsClassifier API scikit-learn](http://scikit-learn.org/stable/modules/generated/sklearn.neighbors.KNeighborsClassifier.html)\n"
    ]
   },
   {