We have provided a short set of references to books and significant Web sites for each chapter (and a couple for the Appendix).

The books have been chosen to provide additional background or advanced information on topics that we only treat briefly in the book.

We have only included references to Web sites that host standards documents and similar sources of definitive reference material. We have omitted blog posts, wikis, tutorial, FAQ lists and other unrefereed material and ephemera, which may be unreliable and often go out of date or disappear. There is a wealth of such material available, which you will be able to find using a search engine.

If you think we have omitted some important reference, please let us know about it and we will consider adding it to the list.