Copyright (c) 2000 David Wood.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections , with no Front-Cover Texts and with no Back-Cover Texts. A copy of the license is available at http://www.gnu.org/copyleft/fdl.html.