diff --git a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/textbook.en.md b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/textbook.en.md
deleted file mode 100644
index 18890e2a5..000000000
--- a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/textbook.en.md
+++ /dev/null
@@ -1,4 +0,0 @@
----
-title: 'The thin lens'
----
-
diff --git a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/textbook.es.md b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/textbook.es.md
deleted file mode 100644
index 4bda1097a..000000000
--- a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/textbook.es.md
+++ /dev/null
@@ -1,4 +0,0 @@
----
-title: 'La lente delgada '
----
-
diff --git a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/textbook.fr.md b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/textbook.fr.md
deleted file mode 100644
index a69dee1b1..000000000
--- a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/textbook.fr.md
+++ /dev/null
@@ -1,4 +0,0 @@
----
-title: 'Le lentille mince'
----
-
diff --git a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/topic.es.md b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/topic.es.md
deleted file mode 100644
index a2306078f..000000000
--- a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/topic.es.md
+++ /dev/null
@@ -1,4 +0,0 @@
----
-title: 'Modelando un espejo'
----
-
diff --git a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/topic.fr.md b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/topic.fr.md
deleted file mode 100644
index 284a0b0ee..000000000
--- a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/topic.fr.md
+++ /dev/null
@@ -1,4 +0,0 @@
----
-title: 'Le miroir'
----
-