# Strange unrecognized control sequence error with beamer

I was trying to include bibliography in my presentation, but I get this error:

! Undefined control sequence.
\beamer@sort #1#2->\long \def \beamer@todo
{#1}\def \beamer@ospec {}\beamer@...


I get this error when I run pdflatex second time, the first run completes with no errors and references appear in the bibliography.

My bibliography looks like this:

\begin{frame}
\frametitle{References}
\begin{thebibliography}{nevell1984unified}
\bibitem[Bandaru and Deb, 2010]{deb10}
Bandaru, S. and Deb, K. (2010).
\newblock Automating discovery of innovative design principles through
optimization.
\newblock Technical Report 2010001, Kanpur Genetic Algorithms Laboratory,
Indian Institute of Technology, Kanpur.

\bibitem[Anderson, 1996]{anderson96}
Anderson, J. (1996).
\newblock {\em {The architecture of cognition}}.
\newblock Lawrence Erlbaum.

\end{thebibliography}
\end{frame}


I have unsuccessfully tried using bibtex to generate the bibliography but I keep getting equally strange errors, like \newblock unrecognized or \item missing from list environment etc, no matter what I do. If I remove the bibliography, everything works fine apart from the unknown citations warnings. Is there a simple working way to include the bibliography in beamer?

• I'm able to compile this frame in a beamer presentation without problems. Please post a minimal example which produces that error. – Stefan Kottwitz Jan 16 '11 at 13:09
• Nevermind, I located the problem, it was the \uspackage{cite} in my preamble. After commenting it everything is working fine. Thanks. – Dronacharya Jan 16 '11 at 13:40
• which is why it's always a good idea to try to produce a minimal example before asking a new question. Anyway, you could post your comment as an answer and accept it, so that this question doesn't remain unanswered. – Juan A. Navarro Jan 16 '11 at 13:54
• But if he had located the problem by using a minimum example by spending 15 minutes and not posted it, thousands of other users would have to do the same repeatedly wasting hundreds of man-hours. Now others can look at this answer and save time. – highBandWidth Mar 13 '17 at 19:28

I located the problem, it was the \usepackage{cite} in my preamble. After commenting it everything is working fine.