diff --git a/AABB_tree/include/CGAL/AABB_face_graph_triangle_primitive.h b/AABB_tree/include/CGAL/AABB_face_graph_triangle_primitive.h
index 995699592fb..215ceb41107 100644
--- a/AABB_tree/include/CGAL/AABB_face_graph_triangle_primitive.h
+++ b/AABB_tree/include/CGAL/AABB_face_graph_triangle_primitive.h
@@ -138,7 +138,7 @@ public:
   typedef Kernel_traits<Point>::Kernel::Triangle_3 Datum;
   /*!
   Id type:
-  - boost::graph_traits<FaceGraph>::face_descriptor Id if OneFaceGraphPerTree is `CGAL::Tag_true
+  - boost::graph_traits<FaceGraph>::face_descriptor Id if OneFaceGraphPerTree is `CGAL::Tag_true`
   - std::pair<boost::graph_traits<FaceGraph>::face_descriptor, FaceGraph> Id if OneFaceGraphPerTree is `CGAL::Tag_false`
   */
   Unspecified_type Id;
diff --git a/AABB_tree/include/CGAL/AABB_halfedge_graph_segment_primitive.h b/AABB_tree/include/CGAL/AABB_halfedge_graph_segment_primitive.h
index b4e34d59842..df99d4a6992 100644
--- a/AABB_tree/include/CGAL/AABB_halfedge_graph_segment_primitive.h
+++ b/AABB_tree/include/CGAL/AABB_halfedge_graph_segment_primitive.h
@@ -153,7 +153,7 @@ public:
   typedef Kernel_traits<Point>::Kernel::Segment_3 Datum;
   /*!
   Id type:
-  - boost::graph_traits<HalfegdeGraph>::edge_descriptor Id if OneHalfegdeGraphPerTree is `CGAL::Tag_true
+  - boost::graph_traits<HalfegdeGraph>::edge_descriptor Id if OneHalfegdeGraphPerTree is `CGAL::Tag_true`
   - std::pair<boost::graph_traits<HalfegdeGraph>::edge_descriptor, HalfegdeGraph> Id if OneHalfegdeGraphPerTree is `CGAL::Tag_false`
   */
   Unspecified_type Id;