A family of Microsoft word processing software products for creating web, email, and print documents.
Extra Step:
I had to make the Developer tab visible, then click on Macro Security, and put a tick in the box
"Trust access to the VBA project object model".
I was then able to select the "Developer" tab, click on "Visual Basic" click on "Tools", and select the "References" (which was no longer greyed-out) as it had been prior to making the above changes.
Giving trusted access to the VBA project object model is both unnecessary for any of the macros discussed in this thread and is unwise for any situation where you don't need macros to do their own editing of your VBA environment. That setting allows macro viruses, for example, to write code to an Office application that could be used to wipe out all your data. Trusted access to the VBA project object model is not needed in order to set a reference to an Office application.