\begin{thebibliography}{1}

\bibitem{LPF}
League For~Programming Freedom.
\newblock Against software patents.
\newblock {\em Communications of the ACM}, January 1992.

\bibitem{hackers}
Steven Levy.
\newblock {\em Hackers}.
\newblock Dell Publishing, New York, New York, 1984.

\bibitem{free-sw}
Richard Stallman.
\newblock What is {F}ree {S}oftware.
\newblock http://www.gnu.org/philosophy/free-sw.html.

\bibitem{PTO}
Various.
\newblock Our business: An introduction to the pto.
\newblock http://www.uspto.gov/web/menu/intro.html.

\end{thebibliography}