diff --git a/lectures/static_in_classes.md b/lectures/static_in_classes.md
index ffb277b..e48feb0 100644
--- a/lectures/static_in_classes.md
+++ b/lectures/static_in_classes.md
@@ -2,7 +2,7 @@ Keyword `static` inside classes
 ---
 
 <p align="center">
-  <a href="https://youtu.be/blah"><img src="https://img.youtube.com/vi/blah/maxresdefault.jpg" alt="Video" align="right" width=50% style="margin: 0.5rem"></a>
+  <a href="https://youtu.be/ggNCjDPShrA"><img src="https://img.youtube.com/vi/ggNCjDPShrA/maxresdefault.jpg" alt="Video" align="right" width=50% style="margin: 0.5rem"></a>
 </p>
 
 - [Keyword `static` inside classes](#keyword-static-inside-classes)
diff --git a/readme.md b/readme.md
index 4f88dec..f4a9bc3 100644
--- a/readme.md
+++ b/readme.md
@@ -437,7 +437,7 @@ Headers with classes
 </details>
 
 <details>
-<summary>Keyword <code>static</code> outside of classes</summary>
+<summary>Keyword <code>static</code> <b>outside</b> of classes</summary>
 
 ----------------------------------------------------------
 [![Video thumbnail](https://img.youtube.com/vi/7cpPQunjv4s/maxresdefault.jpg)](https://youtu.be/7cpPQunjv4s)
@@ -451,6 +451,20 @@ Headers with classes
 ----------------------------------------------------------
 </details>
 
+<details>
+<summary>Keyword <code>static</code> <b>inside</b> classes</summary>
+
+----------------------------------------------------------
+[![Video thumbnail](https://img.youtube.com/vi/ggNCjDPShrA/maxresdefault.jpg)](https://youtu.be/ggNCjDPShrA)
+
+[Lecture script](lectures/static_in_classes.md)
+- Using `static` class methods
+- Using `static` class data
+- What is `static` in classes useful for?
+
+----------------------------------------------------------
+</details>
+
 ---
 
 ## PS