# How to write the result of a citation to a file?

You can't use \cite because this has several instruction for printing the citation key.

You need to use \[email protected]<key>, for instance like this:

\documentclass{article}

\newwrite\tempfile
\AtBeginDocument{\immediate\openout\tempfile=\jobname.txt}
\makeatletter
\newcommand{\writecite}[1]{%
\@for\next:=#1\do{%
\immediate\write\tempfile{%
\@ifundefined{[email protected]\next}{[<\next>]}{[\csname [email protected]\next\endcsname]}%
}%
}%
}
\makeatother

\begin{document}
\cite{Ab,Cd}

\writecite{Ab,Cd}

\begin{thebibliography}{1}
\bibitem{Ab} Author, title, 2016.
\bibitem{Cd} Common, Second, 2015.
\end{thebibliography}

\end{document}


## Contents after the first run

[<Ab>]
[<Cd>]


## Contents after the second run

[1]
[2]