# Using \bibliography in both slides and notes in Beamer

In my presentations, the projection is behind me and I see the slide notes in my laptop. I'm currenly using Pympress.

I want to show the bibliography in presentation and also in the notes. So I use \bibliography twice.

As I can see, it's no problem for Latex, but the replication of the \bibliography command is not appreciated by Bibtex.

My MWE:

\documentclass[12pt]{beamer}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{pgfpages}
\setbeameroption{show notes on second screen=right}
\bibliographystyle{amsalpha}

\begin{document}

\begin{frame}
File organization: \cite{folkzoellick1992}

Data structures: \cite{langsam1990}

\note{Books}
\end{frame}

\begin{frame}
References for the audience:
\bibliography{mybib}

\note{
References for me:
\bibliography{mybib}
}
\end{frame}

\end{document}


The mybib.bib file is:

% Encoding: UTF-8
@Book{langsam1990,
title     = {Data structures using C and C++},
publisher = {Prentice-Hall},
year      = {1990},
author    = {Langsam, Y. and Augenstein, M. J. and Tenenbaum, A .M.},
}

@Book{folkzoellick1992,
title      = {File structures},
publisher  = {Addison-Wesley Publishing Company, Inc.},
year       = {1992},
author     = {Folk, M.J. and Zoellick, B.},
}


The resulting PDF is okay, but Bibtex issues an error. This is not a major issue, but the error keeps bugging me.

This is thebibtex output:

This is BibTeX, Version 0.99d (TeX Live 2017/Debian)
The top-level auxiliary file: t.aux
The style file: amsalpha.bst
Illegal, another \bibdata command---line 27 of file t.aux
: \bibdata
:         {mybib}
I'm skipping whatever remains of this command
Database file #1: mybib.bib
(There was 1 error message)


Perhaps there's a command to print the references I'm unaware of. I googled and found \printbibliography from biblatex package. As I don't know if I mixing Bibtex and BibLatex is a good practice, I'm looking for some advice.

So, what I am missing? :-)

In case you decide to fully switch to biblatex (to be compiled with biber instead of bibtex), you could achieve a similar citation style with

\documentclass[12pt]{beamer}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{pgfpages}
\setbeameroption{show notes on second screen=right}
\usepackage[style=alphabetic]{biblatex}
\setlength{\biblabelsep}{-0.5cm}

\begin{filecontents}{mybib.bib}
% Encoding: UTF-8
@Book{langsam1990,
title     = {Data structures using C and C++},
publisher = {Prentice-Hall},
year      = {1990},
author    = {Langsam, Y. and Augenstein, M. J. and Tenenbaum, A .M.},
}

@Book{folkzoellick1992,
title      = {File structures},
publisher  = {Addison-Wesley Publishing Company, Inc.},
year       = {1992},
author     = {Folk, M.J. and Zoellick, B.},
}
\end{filecontents}

\begin{document}

\begin{frame}
File organization: \cite{folkzoellick1992}

Data structures: \cite{langsam1990}

\note{Books}
\end{frame}

\begin{frame}
References for the audience:

\printbibliography

\note{
References for me:
\printbibliography
}
\end{frame}

\end{document}


• Would you advise to "upgrade" to biblatex? I mean in a general way, disregarding my specific question. Aug 30 '18 at 13:37
• @Jander I would not call it upgrade, but switch. And yes, I would recommend biblatex, it is much more powerful and easier to customise. The only usecase I see for bibtex is for preparing submissions to journals which often don't accept biblatex. Aug 30 '18 at 13:40
• I'll take a closer look to biblatex. Thanks. Sep 3 '18 at 13:16