I bought Nation through Ebookwise.com and am happily reading it on the device. Except that, this being a Pratchett novel, there are footnotes, and I can't figure out how to see them. I've tried poking at the little star indicator, checking the end of the chapter, and very warily looking at the end of the book.
I assume the notes exist somewhere even in the IMP format. I found
https://www.mobileread.com/forums/showthread.php?t=31432 a thread here to do with seeing the footnotes on the Cybook...