Copyright © 2001 John D Lamb.
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 and the SGML document source are included with this document
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The web page version of this document was generated using the Perl script sparse.pl together with some free tools.
John Sharp has made helpful comments on the first draft of this document.