# Natbib citation error

One of my citations is breaking my document. If I build it with the citation uncalled in the document and a fresh .bbl file, the document builds fine. If I try and call the citation, it breaks the build process and even if I remove the citation, I have to rebuild the .bbl file for a proper build.

Here is the citation, its quite small and simple but something is happening that I can't seem to fix.

@misc{Perez1,
author = {Perez, Hernain David},
booktitle = {CSCMP's Supply Chain Quarterly},
pages = {4},
title = {{Supply Chain Strategies: Which one hits the mark?}},
url = {http://www.supplychainquarterly.com/print/­supply­chain­strategies­which­one­hits­the­mark},
year = {2013}
}


I should state that I'm importing my .bib file from Mendeley and haven't had a problem with any other citation. I've move the citation to the first entry on the bib file.

I'm calling the citation with \citet{Perez1} and my master document is using \usepackage[round]{natbib}. The error I'm receiving is an Undefined control sequence.\Generic Error, not exactly helpful.

MWE:

 \usepackage[round]{natbib}
\begin{document}
Test citation \citep{Perez1}.
\bibliographystyle{plainnat}
\bibliography{Skripsie}
\end{document}


\@outlinefile=\write3 Package natbib Warning: Citation Perez1' on page 1 undefined on input line 15. (C:\Users\reece\Documents\Engineering\Skripsie\Test.bbl [1 {C:/Users/reece/AppData/Local/MiKTeX/2.9/pdftex/config/pdftex.map}] ! Undefined control sequence. \GenericError ... 4 \errhelp \@err@ ... l.12 ...­strategies­which­one­hits­the­mark} . The control sequence at the end of the top line of your error message was never \def'ed. If you have misspelled it (e.g.,\hobx'), type I' and the correct spelling (e.g.,I\hbox'). Otherwise just continue, and I'll forget about whatever was undefined.

• In my experiment I get no error; the output is slightly better if you add \usepackage{url}, however. Aug 10, 2015 at 10:17
• Make a complete example, starting with \documentclass. And test it in some empty folder along with a small bib containing only the bib entry, to ensure that one can reproduce the error with this example. Aug 10, 2015 at 10:24
• Hi guys, thanks for the feedback. There was a problem with the URL. I just removed the entire URL from the citation and all went well. Aug 10, 2015 at 13:30

There was a problem with the url field (I suppose direcly copied on the web), which probably had some invisible character in it. I retyped the url, changed the category from @misc to @article since it comes from a journal on line, loaded the url package to break long urls at the end of line.

I also propose to use bblatex with option natbib (it emulates the \citet and citep commands from natbib) and style=authoryear. The advantage, with backend=biber is you can input accented letters directly on the keyboard, since biber understands utf8.

I corrected the url, which wasn't exact, and the author's first name, which precisely has an accented letter.

Code with natbib + bibtex:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[showframe]{geometry}
\usepackage[round]{natbib}
\usepackage{url}

\begin{document}

\citet{Perez1}.

\bibliographystyle{plainnat}
\bibliography{Skripsie}


.bib file for bibtex

@article{Perez1,
author = {Perez, Hern\'{a}in David},
journal = {CSCMP's Supply Chain Quarterly},
pages = {4},
title = {{Supply Chain Strategies: Which one hits the mark?}},
url = {{http://www.supplychainquarterly.com/print/20130306-supply-chain-strategies-which-one-hits-the-mark/}},
year = {2013},
}


Code with biblatex + biber:*

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage[showframe]{geometry}
\usepackage[english = british]{csquotes}
\usepackage[english]{babel}
\usepackage[natbib, style=authoryear, backend=bibtex]{biblatex}

\begin{document}

A citation: \citet{Perez1}
\printbibliography

\end{document}

\end{document}


.bib file for biber;

@article{Perez1,
author = {Perez, Hernán David},
journal = {CSCMP's Supply Chain Quarterly},
pages = {4},
title = {Supply Chain Strategies: Which one hits the mark?},
url = {http://www.supplychainquarterly.com/print/20130306-supply-chain-strategies-which-one-hits-the-mark/},
year = {2013},
}