\begin{thebibliography}{1}

\bibitem{fourman77b}
Michael~P. Fourman.
\newblock Comparaison des r\'eeles d'un topos; structures lisses sur un topos
  \'{e}l\'{e}mentaire.
\newblock {\em Cah. G\'{e}om. Top. Diff.}, 16(3):233--239, 1977.

\end{thebibliography}
