\begin{thebibliography}{GAP02}

\bibitem[GAP02]{GAP4}
The GAP Group, Aachen, St~Andrews.
\newblock {\em {GAP} -- {G}roups, {A}lgorithms, and {P}rogramming, Version
  4.3}, 2002.
\newblock http://www.gap-system.org.

\bibitem[Lam85]{La85}
Leslie Lamport.
\newblock {\em \LaTeX: A Document Preparation System}.
\newblock Addison-Wesley, 1985.

\end{thebibliography}
