Extra backslash from accent in citations using \bibliographystyle{alpha}

Question

I would like to use the bibliographystyle alpha to get author-date references. A few of my authors (Apéry, Poénaru) have names with an accent over the third letter. Those are indicated by \'{e} in the bib file (eg Ap\'{e}ry). When Bibtex process the bib file, it incorporates the accent. Not surprisingly, I get an error message

Runaway argument? {{Ap\}86} \par \bibitem [{Ap\}86]{K2-42} {Ap\'ery, Fran\c {c}ois}.

when processing via Latex after running Bibtex. It doesn't have any trouble with those names unless it's the first author (as in the second bib entry in the example below).

Eg in the MWE below, the bbl file shows

\begin{thebibliography}{{Ap\\}86}
\bibitem[{Ap\}86]{K2-42}
{Ap\'ery, Fran\c{c}ois}.
\newblock {La surface de Boy}.
\newblock {\em Advances in Mathematics}, 61:185--266, 1986.
\bibitem[{Jon}87]{K2-43}
{Jones, V. and Ap\'ery, Fran\c{c}ois}.
\newblock {A non-existent paper}.
\newblock {\em Advances in Mathematics}, 61:185--266, 1987.
\end{thebibliography}

(Note Ap\ in the first line and in the first \bibitem). How can I prevent this from happening? I tried a few things, eg inserting {} before the accent, enclosing the names in extra braces. This seems obscure but presumably someone has encountered this issue before.

Here is a MWE

\documentclass[11pt]{book}
\begin{document}
\chapter{Knot theory}
\section{Introduction}
This citation produces an error \cite{K2-42} 
but this one does not produce an error \cite{K2-43}
\begin{filecontents}{backtest.bib}
@article{K2-42,
  author = {{Ap'ery, Fran\c{c}ois}},
  title = {{La surface de Boy}},
  journal = {Advances in Mathematics},
  volume = {61},
  year = {1986},
  pages = {185--266},
}
@article{K2-43,
  author = {{Jones, V. and Ap'ery, Fran\c{c}ois}},
  title = {{A non-existent paper}},
  journal = {Advances in Mathematics},
  volume = {61},
  year = {1987},
  pages = {185--266},
}
\end{filecontents}
\bibliographystyle{alpha}
\bibliography{backtest}
\end{document}

Answer 1

The main problem here are excessive curly braces around names.

You don't want double brace around the contents of name fields. That will stop BibTeX processing the individual names as names and will stop parsing them into first and last name. Get rid of the double braces unless you want to reference a "corporate" (non-person) author (Using a 'corporate author' in the "author" field of a bibliographic entry (spelling out the name in full)).

On the other hand, you will need to wrap the accented characters into an additional pair of curly braces to have BibTeX understand them correctly for sorting and abbreviation purposes. See How to write “ä” and other umlauts and accented letters in bibliography?.

In your case that means that the names should be given as

\documentclass[11pt]{article}
\begin{filecontents}{\jobname.bib}
@article{K2-42,
  author  = {Ap{'e}ry, Fran{\c{c}}ois},
  title   = {La surface de Boy},
  journal = {Advances in Mathematics},
  volume  = {61},
  year    = {1986},
  pages   = {185-266},
}
@article{K2-43,
  author  = {Jones, V. and Ap{'e}ry, Fran{\c{c}}ois},
  title   = {A non-existent paper},
  journal = {Advances in Mathematics},
  volume  = {61},
  year    = {1987},
  pages   = {185-266},
}
\end{filecontents}
\begin{document}
This citation produces an error \cite{K2-42} 
but this one does not produce an error \cite{K2-43}
\bibliographystyle{alpha}
\bibliography{\jobname}
\end{document}