It comes up in the X'Eye demo (previously posted here) at http://www.youtube.com/watch?v=fvRve...ailpage#t=537s (8:56).
I think this is the reference I saw. (The trick is to search for "electronic book". How quaint!)
http://www.sega-16.com/forum/archive...p/t-15450.html
http://www.gamegavel.com/item.cgi?show_item=0000691591