Using \bibliography in both slides and notes in Beamer

Question

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.},
  address   = {New Jersey},
}

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

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? :-)

Answer 1

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}
\addbibresource{mybib.bib}
\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.},
  address   = {New Jersey},
}

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