diff --git a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/01.plane-refracting-surface-main/textbook.en.md b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/01.plane-refracting-surface-main/textbook.en.md
index cfc0c836a..9db0b7194 100644
--- a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/01.plane-refracting-surface-main/textbook.en.md
+++ b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/01.plane-refracting-surface-main/textbook.en.md
@@ -1,5 +1,7 @@
 ---
 title: 'Refracting surface '
+published: false
+visible: false
 ---
 
 ### Spherical refracting surface in paraxial approximation.