diff --git a/README.md b/README.md
index 76d1ab6a36060528e951397795b3e0a6d939c512..cd4e8ae64aa877bfb86bae87b505a750a7a94a0a 100644
--- a/README.md
+++ b/README.md
@@ -18,8 +18,11 @@ classDiagram
   class Subject
   <<Abstract>> Subject
   Subject "1" --> "*" Observer
-  Subject : +attach(Observer)
-  Subject : +detach(Observer)
+  Subject : +attach(Observer) void
+  Subject : +detach(Observer) void
+  Subject : -notifyObservers() void
+  Subject : -notifyObservers(Object) void
+  
   class Observer
   <<interface>> Observer
 ```