diff --git a/README.md b/README.md
index 14215a9..707192e 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ submitted (as an update of the Core_DOM entry) at a later stage.
 ## How to build
 
 ```
-isabelle build -d Core_DOM Core_DOM 
+isabelle build -D Core_DOM
 ```
 
 ## Authors