diff --git a/README.md b/README.md
index c9d19fe..0368497 100644
--- a/README.md
+++ b/README.md
@@ -126,6 +126,10 @@ At the moment this is not useful for anyone but myself, if at some point I find
           * [Virtual Memory, Disk Devices](https://minnie.tuhs.org/CompArch/Lectures/week10.html)
           * [Filesystems & Their Performance](https://minnie.tuhs.org/CompArch/Lectures/week11.html)
           * [IPC, Synchronisation and Threads](https://minnie.tuhs.org/CompArch/Lectures/week12.html)
+       * Threads
+         * ["An Introduction to Programming with Threads"](https://s3.amazonaws.com/content.udacity-data.com/courses/ud923/references/ud923-birrell-paper.pdf) by Birrell 📰 🆓
+         * POSIX Threads (PThreads)
+           * [PThreads / POSIX Threads Coding Examples](https://computing.llnl.gov/tutorials/pthreads/) 📰 🆓
        * Virtual Memory
          * mmap
            * [How processes get more memory](https://www.youtube.com/watch?v=XV5sRaSVtXQ)
diff --git a/resources/topic-graph.mmd b/resources/topic-graph.mmd
index 1a9d1fd..0799873 100644
--- a/resources/topic-graph.mmd
+++ b/resources/topic-graph.mmd
@@ -40,6 +40,17 @@ graph TD
 
   SRE --> OPS[Operations]
     OPS --> OS[Operating Systems]
+      OS --> MM[Memory]
+        MM --> Heap
+        MM --> Stack
+        MM --> PAG[Pagination]
+      OS --> PRO[Process]
+        PRO --> IPC[Inter Process Communication]
+          IPC --> IPCM[Message Passing]
+          IPC --> IPCSM[Shared Memory]
+      OS --> CCY[Concurrency]
+        CCY --> Thread
+          Thread --> PThread
     OPS --> OPSOPS[Operational]
       OPSOPS --> Ter[Terminal]
         Ter --> Bash
diff --git a/resources/topic-graph.png b/resources/topic-graph.png
index f37baf4..ab68f19 100644
Binary files a/resources/topic-graph.png and b/resources/topic-graph.png differ