diff --git a/distributed-file-systems/README.md b/distributed-file-systems/README.md
index bcaacd2..7676031 100644
--- a/distributed-file-systems/README.md
+++ b/distributed-file-systems/README.md
@@ -11,3 +11,5 @@
 * [Coda](http://www.coda.cs.cmu.edu/ljpaper/lj.html)
 
 * [Frangipani](https://pdos.csail.mit.edu/6.824/papers/thekkath-frangipani.pdf)
+
+* [Actor Formalism](http://worrydream.com/refs/Hewitt-ActorModel.pdf)
\ No newline at end of file
diff --git a/distributed_systems/a-universal-modular-actor-formalism-for-artificial-intelligence.pdf b/distributed_systems/a-universal-modular-actor-formalism-for-artificial-intelligence.pdf
index cdc9fa7..7042cff 100644
Binary files a/distributed_systems/a-universal-modular-actor-formalism-for-artificial-intelligence.pdf and b/distributed_systems/a-universal-modular-actor-formalism-for-artificial-intelligence.pdf differ