When I wrote my book, there was a lot of material that I would have liked to have mentioned, but which I had to leave out. After I completed it, new articles and papers also appeared that I would also have mentioned had they been available earlier. Furthermore, I've since come across some older interesting pieces that I didn't find out about in time.

Some of this stuff may be of interest to readers, so I present references to it here.



Elsewhere on this site:

Copyright © Richard A. Bartle (
17th June, 2003.