The External Topic References dialog identifies all external topics (links to external HTML topics, URLs to Web pages, etc.) that are referenced in your project. Use it to modify these references and remove them from the project.
References to Selected Topic: Displays a list of all references to the external topic selected from the list on the right.
All External Topics: Displays a list of all external topics that are referenced in the project. When you select an item from this list, the references on the left also change.
Edit: For hyperlink references, opens the topic with the link in the WYSIWYG Editor so you can modify or remove it. For table of contents references, displays the properties for the book or page so it can be modified.
Delete: Removes the reference from the table of contents.