\begin{thebibliography}{1}

\bibitem{gs:discretemaths}
David Gries and Fred B.Schneider.
\newblock {\em A logical approach to Discrete Mathematics}.
\newblock Springer-Verlag, 1993.

\bibitem{dek:taocp:i}
Donald~E. Knuth.
\newblock {\em The Art of Computer Programmimg, volume 1: Fundamental
  Algorithms}.
\newblock Addison-Wesley, 1998.

\bibitem{rosen:discretemaths}
Kenneth Rosen.
\newblock {\em Discrete Mathematics}.

\end{thebibliography}
