diff --git a/README.md b/README.md
index 60106f2..cc3d10c 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,2 @@
 # Raspberry-Pi-versions-and-revisions
+Based on: https://www.raspberrypi-spy.co.uk/2012/09/checking-your-raspberry-pi-board-version/