diff --git a/20.test/35.temporaryDsystem/20.b/textbook.es.md b/20.test/35.temporaryDsystem/20.b/textbook.es.md
index 61bfcd813..ed67b84b4 100644
--- a/20.test/35.temporaryDsystem/20.b/textbook.es.md
+++ b/20.test/35.temporaryDsystem/20.b/textbook.es.md
@@ -1,10 +1,10 @@
 ---
 lessons:
-    - slug: test01-es
+    - slug: test01-Les
       order: 2
-    - slug: test02-es
+    - slug: test02-Les
       order: 1
-    - slug: test03-es
+    - slug: test03-Les
       order: 3
 ---