diff --git a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/03.optical-systems-vergence/textbook.en.md b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/03.optical-systems-vergence/textbook.en.md
deleted file mode 100644
index 706b62099..000000000
--- a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/03.optical-systems-vergence/textbook.en.md
+++ /dev/null
@@ -1,4 +0,0 @@
----
-title: 'Optical systems'
----
-