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:

    \bibitem[Bandaru and Deb, 2010]{deb10}
      Bandaru, S. and Deb, K. (2010).
      \newblock Automating discovery of innovative design principles through
      \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.


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?

  • 2
    I'm able to compile this frame in a beamer presentation without problems. Please post a minimal example which produces that error.
    – Stefan Kottwitz
    Commented Jan 16, 2011 at 13:09
  • Nevermind, I located the problem, it was the \uspackage{cite} in my preamble. After commenting it everything is working fine. Thanks. Commented Jan 16, 2011 at 13:40
  • 1
    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. Commented Jan 16, 2011 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. Commented Mar 13, 2017 at 19:28

1 Answer 1


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

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