diff --git a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/40.electromagnetism/05.first-steps/textbook.es.md b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/40.electromagnetism/05.first-steps/textbook.es.md
index a598c4b81..f38d213ee 100644
--- a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/40.electromagnetism/05.first-steps/textbook.es.md
+++ b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/40.electromagnetism/05.first-steps/textbook.es.md
@@ -4,7 +4,7 @@ published: true
 routable: true
 visible: false
 lessons:
-    - slug: Estructuración-g12-electromagnetismo
+    - slug: estructuración-g12-electromagnetismo
       order: 1
 ---