Needless to say, many errors, omissions and other imperfections will still be discovered by people far more knowledgeable in this topic than I can be, and I would be very grateful to them if they were kind enough to point out those mistakes, or to make suggestions so that this material could be further improved.

The author's name and e-mail address:
Hervé Guérin, rvp_guerin@yahoo.fr

Last updated: 28 May 2007