How do I create something like this without getting any errors?

\begin{thm}[\cite[page 10]{ABC2011}]
...
\end{thm}


I tried putting various things into {...} brackets, but not eliminating any errors. I probably have misunderstood something about how LaTeX works in the background and the AMS packet:

\usepackage[amsmath,thmmarks]{ntheorem}

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Mask the content of thm' s optional argument with an additional set of braces.

EDIT: For what it's worth, with ntheorem loaded one needs two additional sets of braces.

\documentclass{article}

\usepackage{ntheorem}

\newtheorem{thm}{Theorem}

\begin{document}

\begin{thm}[{{\cite[page 10]{ABC2011}}}]
A theorem.
\end{thm}

\begin{thebibliography}{9}
\bibitem{ABC2011} A bibitem.
\end{thebibliography}

\end{document}

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Thanks for the fast response. I get these errors, when I do that: Argument of \@citex has an extra }. Runaway argument? page 10\color@endgroup Latex Error: Paragraph ended before \@citex was complete. Latex Error: Extra }, or forgotten \endgroup. – user46365 May 1 '11 at 19:01
It must be some other package which is causing troubles :\ – user46365 May 1 '11 at 19:03
Tried it on a fresh file and it worked like a charm.. bummer. – user46365 May 1 '11 at 19:04
@user46365: What packages that might affect theorems do you use (amsthm, ntheorem)? What document class? A working example would be even better. – lockstep May 1 '11 at 19:04
@user46365: Strange enough, my example still works if I load amsthm, but not with ntheorem. Obviously you don't use ntheorem if it works for you now. – lockstep May 1 '11 at 19:07
\documentclass{article}
\usepackage{ntheorem}
\newtheorem{thm}{Theorem}

\begin{document}

\begin{thm}[\protect{\cite[page 10]{ABC2011}}]
A theorem.
\end{thm}

\begin{thebibliography}{9}
\bibitem{ABC2011} A bibitem.
\end{thebibliography}

\end{document}


regards

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thanks marco for your help. – user46365 May 1 '11 at 19:23

I have another solution. I don't use the package theorem.

I just change [\cite[page 10]{ABC2011}] to --> {[\cite[page 10]{ABC2011}]}.

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Welcome! This answer has already been given by others, please make sure that your answer is really a "new answer" before clicking that button. Small improvements on existing answers can be suggested in the comments or with the "edit" button. – T. Verron Sep 29 '14 at 14:19