diff --git a/README.md b/README.md
index dff24f8..1713a3b 100644
--- a/README.md
+++ b/README.md
@@ -241,7 +241,7 @@ For machine learning, the initial step involved tailoring the features for the m
 <br>[ml_decision_tree.ipynb](notebooks/ml_decision_tree.ipynb) (version 03.07)
 
 
-### Cluster-analysis
+## Cluster-analysis
 (version 03.07)
 [](notebooks/...)