diff --git a/river/bandit/bayes_ucb.py b/river/bandit/bayes_ucb.py
index 539d62d3d9..7eec7f1de9 100644
--- a/river/bandit/bayes_ucb.py
+++ b/river/bandit/bayes_ucb.py
@@ -54,7 +54,7 @@ class BayesUCB(bandit.base.Policy):
     Sum: 841.
 
     Reference
-    --------
+    ---------
     [^1]: [Kaufmann, Emilie, Olivier Cappé, and Aurélien Garivier. "On Bayesian upper confidence bounds for bandit problems." Artificial intelligence and statistics. PMLR, 2012.](http://proceedings.mlr.press/v22/kaufmann12/kaufmann12.pdf)
 
     """