\begin{thebibliography}{1}

\bibitem{kn:base}
Klaus Grue.
\newblock A logiweb base page.
\newblock Logiweb-dokument tilg\ae{}ngelig p\aa{} hjemmesiden:
  \url{http://www.diku.dk/~grue/logiweb/20050502/home/grue/base/GRD-2005-06-03%
-UTC-15-49-33-495567}.

\bibitem{kn:peano}
Klaus Grue.
\newblock Peano arithmetic.
\newblock Logiweb-dokument tilg\ae{}ngelig p\aa{} hjemmesiden:
  \url{http://www.diku.dk/~grue/logiweb/20050502/home/grue/peano-axioms/GRD-20%
05-06-03-UTC-15-58-02-061312}.

\bibitem{kn:mendel}
Elliott Mendelson.
\newblock {\em Introduction to Mathematical Logic}.
\newblock Chapman \& Hall, fourth edition, 1997.

\end{thebibliography}
