diff --git a/docs/conf.py b/docs/conf.py
index 7037bc1..547ff47 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -347,3 +347,5 @@ epub_exclude_files = ['search.html']
 
 # If false, no index is generated.
 #epub_use_index = True
+
+bibtex_bibfiles = ['book_of_algorithms/references.bib']
diff --git a/docs/reference_manual/consts.rst b/docs/reference_manual/consts.rst
index 405d493..fdac88d 100644
--- a/docs/reference_manual/consts.rst
+++ b/docs/reference_manual/consts.rst
@@ -79,7 +79,7 @@ Mathematical constants
 
    mathematical constant, :math:`\pi`
 
-   The :term:`constant` represents the `number π <https://en.wikipedia.org/wiki/Pi>`_.
+   The :term:`constant` represents the number :math:`\pi`.
    It is available symbolically as ``Pi`` or numerically through ``N(Pi)``.
 
    This is a :term:`cached constant` which is recalculated only when
