FWIW, Larry also contributed some of his historical knowledge to the Talk page [1] of the Wikipedia article and also edited the article himself.
Here's a nice bit:
> I chose Z/X/C/V when I was in charge of the user interface design of Apple's Lisa. In addition to their adjacency on the keyboard, I wanted them to have mnemonic value: "X" a cross-out; "V" an inverted caret or proofreader's arrowhead; "C" the first letter of "copy"; the strokes of "Z" tracing a reversal followed by a new path forward. -- Larry Tesler
> Correction: Apparently, my memory was incorrect. The Lisa user interface seems to have used "U" for Undo. On the Mac (as in Gypsy), "U" was and is for Underline. I do not know who chose "Z" for Mac Undo, or why. I suspect that its proximity to the Command key was the reason. -- Larry Tesler
There's more, but it's too much to insert here.
I'm just hoping this isn't someone posing as Larry Tesler.