diff --git a/nlp/4_1_Lexical_Processing.ipynb b/nlp/4_1_Lexical_Processing.ipynb
index 6666ae3..1360da6 100644
--- a/nlp/4_1_Lexical_Processing.ipynb
+++ b/nlp/4_1_Lexical_Processing.ipynb
@@ -262,7 +262,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "NLTK provides support for stemming in the package [*stem*](http://www.nltk.org/api/nltk.stem.html). There are several available stemmers:PorterStemmer, lancaster or WordNetLemmatizer. Check the API for more details."
+    "NLTK provides support for stemming in the package [*stem*](http://www.nltk.org/api/nltk.stem.html). There are several available stemmers:PorterStemmer, lancaster or WordNetLemmatizer. Check the API for more details. Here we are going the output of different stemmers (and the execution time). You can observe that some of them use rules and do not behave properly always (e.g. Porter algorithm)."
    ]
   },
   {