diff --git a/13_Reference/reference.js b/13_Reference/reference.js
index 58db6cc..16f2dd6 100644
--- a/13_Reference/reference.js
+++ b/13_Reference/reference.js
@@ -21,7 +21,7 @@ let x = {
   },
 };
 
-let y = JSON.parse(JSON.stringify(a));
+let y = JSON.parse(JSON.stringify(x));
 
 y.obj.a = 2;