diff --git a/README.md b/README.md
index ded9e31..7318265 100644
--- a/README.md
+++ b/README.md
@@ -3,10 +3,24 @@
 
 <img src="resources/topic-graph.png" width="100%">
 
+### More info
+> Information about the links
+
+* 📕 - Book
+* 👩‍💻 - Project
+* 🎓 - Online Course
+* 🆓 - No money required
+* 💰 - Paid
+
+## References
+
 * Site Reliability Engineering
   * Software Engineering
     * Programming Languages
       * Functional Programming Languages
-        * [Haskell From First Principles](https://github.com/marceloboeira/hffp)
+        * [Haskell From First Principles](https://github.com/marceloboeira/hffp) 📕 💰
       * Systems Programming Languages
-        * [The Rust Programming Language](https://github.com/marceloboeira/trpl)
+        * [The Rust Programming Language](https://github.com/marceloboeira/trpl) 📕 🆓
+  * Operations
+    * Operating Systems
+      * [Introduction to Operating Systems](https://eu.udacity.com/course/introduction-to-operating-systems--ud923) 🎓 🆓
diff --git a/resources/topic-graph.mmd b/resources/topic-graph.mmd
index eef33c0..daeaf1d 100644
--- a/resources/topic-graph.mmd
+++ b/resources/topic-graph.mmd
@@ -12,3 +12,13 @@ graph TD
     PL --> FunPL[Functional Programming Languages]
       FunPL --> Haskell
       FunPL --> Lisp
+  SW --> PT[Programming Topics]
+    PT --> ALG[Algorithms]
+      ALG --> SRT[Sorting]
+      ALG --> CPX[Complexity]
+    PT --> DS[Data Scructures]
+      DS --> Graph[Graph]
+      DS --> T3[Tree]
+      DS --> HS[Hash]
+  SW --> OPS[Operations]
+      OPS --> OS[Operating Systems]
diff --git a/resources/topic-graph.png b/resources/topic-graph.png
index 208455c..6f6a591 100644
Binary files a/resources/topic-graph.png and b/resources/topic-graph.png differ