diff --git a/README.md b/README.md
index 98bffce..c8d24af 100644
--- a/README.md
+++ b/README.md
@@ -160,6 +160,7 @@ Tight surfacemount components need a fanout before routing.
 
  
 ## I want to reuse my constraints to make anoter board without having to put all the numbers in again.  How do I do this?
+Reference: https://www.altium.com/documentation/altium-designer/pcb/constraints-editor#new-custom-constraint-rule
 1. Open the constraint manager (either on the Schematic or PCB depending upon where you set it up)
 1. Open "All Rules" ab
 1. Right click on "Rule Class"