diff --git a/05_classifiers_overview.ipynb b/05_classifiers_overview.ipynb
index 18908f4411af63b7d6c849269a741f6421d619a3..9591ed35e1beade303c791e61c81580138c337c2 100644
--- a/05_classifiers_overview.ipynb
+++ b/05_classifiers_overview.ipynb
@@ -21,6 +21,9 @@
     "- Decision trees\n",
     "- Random forests\n",
     "\n",
+    "- XGboost (https://xgboost.readthedocs.io/en/latest/) (not part of scikit-learn, won many kaggle competitions https://www.kaggle.com/dansbecker/xgboost, offers scikit-learn API https://www.kaggle.com/stuarthallows/using-xgboost-with-scikit-learn)\n",
+    "\n",
+    "\n",
     "For every classifier: some examples for decision surfaces.\n",
     "\n",
     "Historical information ?"
@@ -93,7 +96,9 @@
     "\n",
     "Hard to intepret the internals.\n",
     "\n",
-    "for rbf: gamma parameter is \"decline rate\" of rbf functions, controls smoothness of decision surface.\n"
+    "for rbf: gamma parameter is \"decline rate\" of rbf functions, controls smoothness of decision surface.\n",
+    "\n",
+    "feature scaling is crucial for good performance !"
    ]
   },
   {