The text in the hard-copy version of this book has been produced with LaTeX. The conversion to hypertex has been performed with TeX4ht. The parameters for guiding the translation have been introduced into the preamble of the LaTeX file, but no changes have been introduced into the body of the file.

The figures have been prepared for the hard-copy version of this book with a standard drawing utility. Tim Tinnel scanned the figures from the book for inclusion in this hypertext document, and I am grateful for his contribution.

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