Comment by ricksunny

Thanks for that!

Incidentally, Vannevar Bush's Oral History 14-part document https://archivesspace.mit.edu/repositories/2/resources/687 seems to have served as an early experiment in prototyping hypertext. It has lots of [X-Ref] items throughout that refer to other relevant parts of the (1000+ page) oral history. I'm not aware of that being a common documentation practice at the time, so I see it as an intentional prototype effort on his part.