Copyright Notice

Copyright (C) Allen B. Downey, Paul Bui, Jeffrey Elkner,

and Dafni Hernandez. Permission is granted to copy, distribute and/or

modify this document under the terms of the GNU Free Documentation License,

Version 1.3 or any later version published by the Free Software Foundation;

with Invariant Sections being Preface and Contributor List, no Front-Cover

Texts, and no Back-Cover Texts. A copy of the license is included in the

section entitled “GNU Free Documentation License”.