diff --git a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/40.electromagnetism/50.structure-example/40.n4/textbook.es.md b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/40.electromagnetism/50.structure-example/40.n4/textbook.es.md
index d6c922111..04869f4ce 100644
--- a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/40.electromagnetism/50.structure-example/40.n4/textbook.es.md
+++ b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/40.electromagnetism/50.structure-example/40.n4/textbook.es.md
@@ -1,5 +1,5 @@
 ---
-title: Exemple de structure possible sur le thème "Electromagnétisme"
+title: Ejemplo de una posible estructura sobre el tema "Electromagnetismo"
 published: true
 routable: true
 visible: false
@@ -7,7 +7,8 @@ lessons:
     - slug: structure-example-234-electromagnetism
       order: 3
 ---
-
+<!--caligraphie de l'intégrale double curviligne-->
+$`\def\oint{\displaystyle\mathop{{\int}\mkern-16mu \scriptsize \bigcirc}}`$
 
 ##### Consejos para pensar en la estructuración de este nivel 4