diff --git a/examples/02_Objects_with_effective_homology.ipynb b/examples/02_Objects_with_effective_homology.ipynb
index 427c75d..afad7d4 100644
--- a/examples/02_Objects_with_effective_homology.ipynb
+++ b/examples/02_Objects_with_effective_homology.ipynb
@@ -9,7 +9,7 @@
     "## Introduction\n",
     "\n",
     "The present chapter describes the set of programming tools for handling *objects with effective homology*. The theoretical material may be found in the paper *Constructive Algebraic Topology* by Julio Rubio Garcia and Francis Sergeraert (Available at the web site\n",
-    "[**https://www-fourier.ujf-grenoble.fr/~sergerar/**](https://www-fourier.ujf-grenoble.fr/~sergerar/)). The terminology used in this chapter is compatible with this reference.) The terminology used in this chapter is compatible with this reference.\n",
+    "[**https://www-fourier.ujf-grenoble.fr/~sergerar/**](https://www-fourier.ujf-grenoble.fr/~sergerar/)). The terminology used in this chapter is compatible with this reference. The terminology used in this chapter is compatible with this reference.\n",
     "\n",
     "## Reduction\n",
     "\n",