diff --git a/ts/docx/paragraph/tab-stop.ts b/ts/docx/paragraph/tab-stop.ts
index 1170d4ddac..bbae20a891 100644
--- a/ts/docx/paragraph/tab-stop.ts
+++ b/ts/docx/paragraph/tab-stop.ts
@@ -1,3 +1,4 @@
+// http://officeopenxml.com/WPtab.php
 import { XmlAttributeComponent, XmlComponent } from "../xml-components";
 
 export class TabStop extends XmlComponent {