diff --git a/examples/cross_todo/readme.txt b/examples/cross_todo/readme.txt
index acea8973a..326ed816f 100644
--- a/examples/cross_todo/readme.txt
+++ b/examples/cross_todo/readme.txt
@@ -3,3 +3,5 @@ called by different native user interfaces.
 
 This example builds on the knowledge learned from the cross_calculator example.
 Check it out first to learn how to set up nimrod on different platforms.
+Additional implementations are provided at the external
+https://github.com/gradha/nimrod-crossplatform-todo github repository.