The authors are happy for this document to be freely used by individuals for non-
profit making purposes only, subject to the user accepting full responsibility for any
consequences resulting from use of the information contained herein.
Constructive feedback, comments, or questions are most welcome:
Derek Holliday:
Ugo Manfredi:
Issue 1 April 2003.
drholliday@compuserve.com
ugo.manfredi@mail.wind.it