-uses the built in Henry Spencer's library. In the latter case you need to abide
-by the terms of its copyright:
-
-\begin{verbatim}
-Copyright 1992, 1993, 1994, 1997 Henry Spencer. All rights reserved.
-This software is not subject to any license of the American Telephone
-and Telegraph Company or of the Regents of the University of California.
-
-Permission is granted to anyone to use this software for any purpose on
-any computer system, and to alter it and redistribute it, subject
-to the following restrictions:
-
-1. The author is not responsible for the consequences of use of this
- software, no matter how awful, even if they arise from flaws in it.
-
-2. The origin of this software must not be misrepresented, either by
- explicit claim or by omission. Since few users ever read sources,
- credits must appear in the documentation.
-
-3. Altered versions must be plainly marked as such, and must not be
- misrepresented as being the original software. Since few users
- ever read sources, credits must appear in the documentation.
-
-4. This notice may not be removed or altered.
-\end{verbatim}