diff --git a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
index 79b1afc10..e2c6db9dc 100644
--- a/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
+++ b/00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/04.reference-frames-coordinate-systems/textbook.fr.md
@@ -297,8 +297,8 @@ $`A=\displaystyle\iint_{S_{\smallsmile}} dA`$<br>
 [ES] Esta diferencia en la escritura es muy importante. Por ejemplo en electromagnetismo :<br>
 [FR] Cette différence d'écriture est très importante. Par exemple en électromagnétisme :<br>
 [EN] This difference in writing is very important. For example in electromagnetism :<br>
-$`\forall S_{\circ}  \Oiint_{S_{\smallsmile}} \overrightarrow{B}\cdot\overightarrow{dA}=0`$,<br>
-en general $`\iint_{S_{\smallsmile}} \overrightarrow{B}\cdot\overightarrow{dA}\ne 0`$
+$`\forall S_{\circ}  \oiint_{S_{\smallsmile}} \overrightarrow{B}\cdot\overrightarrow{dA}=0`$,<br>
+en general $`\iint_{S_{\smallsmile}} \overrightarrow{B}\cdot\overrightarrow{dA}\ne 0`$