diff --git a/generate_toc.py b/generate_toc.py
index 03d5699..e877936 100644
--- a/generate_toc.py
+++ b/generate_toc.py
@@ -6,6 +6,7 @@ OUTPUT = "readme.md"
 OUTLINE = "outline.md"
 INPUT = [
         "learning_python3.md",
+        "introduction_to_solid.md",
         "learning_python3_gui.md",
         "learning_git.md",
         "what_is_next.md",
@@ -28,10 +29,13 @@ if __name__ == "__main__":
         output, err = p.communicate()
         output = output.decode().split("\n")
         for line in output:
+            if CMD in line:
+                continue
             if FILTER in line:
                 line = line.replace(FILTER, "(./{}#".format(f))
             if TITLE in line:
                 title = " ".join(f.replace(".md", "").split("_")).capitalize()
+                title = title.replace("/", ": ")
                 line = title
             CONTENT.append(line)
     p = subprocess.Popen(["cp", OUTLINE, OUTPUT], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
diff --git a/Intro_to_Solid.md b/introduction_to_solid.md
similarity index 100%
rename from Intro_to_Solid.md
rename to introduction_to_solid.md
diff --git a/links.md b/links.md
new file mode 100644
index 0000000..0ede021
--- /dev/null
+++ b/links.md
@@ -0,0 +1,4 @@
+# Some links
+
+* [MVC with tkinter](https://www.pythontutorial.net/tkinter/tkinter-mvc/)
+* [principles of OOP](https://www.freecodecamp.org/news/solid-principles-explained-in-plain-english/)
diff --git a/readme.md b/readme.md
index 40f86c1..27a328f 100644
--- a/readme.md
+++ b/readme.md
@@ -119,7 +119,19 @@ Learning python3
       * [Introduction to the requests library](./learning_python3.md#introduction-to-the-requests-library)
    * [Threading](./learning_python3.md#threading)
 
-Created by [gh-md-toc](https://github.com/ekalinin/github-markdown-toc)
+
+
+Introduction to solid
+=================
+
+* [Object-Oriented class design](./introduction_to_solid.md#object-oriented-class-design)
+   * [SOLID](./introduction_to_solid.md#solid)
+      * [Single-Responsibility](./introduction_to_solid.md#single-responsibility)
+      * [Open-Closed Principle](./introduction_to_solid.md#open-closed-principle)
+      * [Liskov Substitution Principle](./introduction_to_solid.md#liskov-substitution-principle)
+      * [Interface Segregation Principle](./introduction_to_solid.md#interface-segregation-principle)
+      * [Dependency Inversion Principle](./introduction_to_solid.md#dependency-inversion-principle)
+
 
 
 Learning python3 gui
@@ -140,7 +152,6 @@ Learning python3 gui
    * [Coding challenge - Login generator with GUI](./learning_python3_gui.md#coding-challenge---login-generator-with-gui-1)
    * [Coding challenge - Trivial pursuit with GUI](./learning_python3_gui.md#coding-challenge---trivial-pursuit-with-gui-1)
 
-Created by [gh-md-toc](https://github.com/ekalinin/github-markdown-toc)
 
 
 Learning git
@@ -160,7 +171,6 @@ Learning git
    * [Cloning the remote project into a new project](./learning_git.md#cloning-the-remote-project-into-a-new-project)
    * [Updating the original project](./learning_git.md#updating-the-original-project)
 
-Created by [gh-md-toc](https://github.com/ekalinin/github-markdown-toc)
 
 
 What is next
@@ -173,5 +183,4 @@ What is next
    * [Books](./what_is_next.md#books)
 * [Linux](./what_is_next.md#linux)
 
-Created by [gh-md-toc](https://github.com/ekalinin/github-markdown-toc)