# Natbib citations suddenly stopped working

I'm using the Eisever journal document class to submit an article. I feel I've compiled the bibtex properly (Latex>Bibtex>Latex>Latex) but nevertheless several citations are just not work. Preamble:

\documentclass[final,3p,times,twocolumn,authoryear]{elsarticle}
\usepackage{url}
\bibliographystyle{elsarticle-harv}
\biboptions{authoryear}


When I compile several of these won't work, I've double checked the arguements to each of the \citep commands and they are good. In fact, I'm also compiling in ShareLaTeX for a different purpose and they work find there.

\section{Background}
Etc Etc Etc \citep{Heidenreich2013} and an estimated 500,000 Canadians \citep{Ross2006}.

Etc Etc including the American Heart Association \citep{Hunt2005}, American College of Cardiology \citep{Hunt2005},
the National Heart Foundation of Australia \citep{Krum2011},
the Cardiac Society of Australia and New Zealand \citep{Krum2011},
the European Society of Cardiology \citep{Jaarsma2009a} and the Canadian Cardiovascular Society \citep{McKelvie2011}.


Specifically let's look at Heidenreich2013 and Ross2006. The first won't compile but the second will. I got the code from Google scholar for each one. But the Heidenreich2013 won't work.

Here are the entries:

}
@article{Ross2006,
title={Treating the right patient at the right time: access to heart failure care},
author={Ross, H and Howlett, J and Arnold, J Malcolm O and Liu, P and O’Neill, BJ and Brophy, JM and Simpson, CS and Sholdice, MM and Knudtson, M and Ross, DB and others},
volume={22},
number={9},
pages={749--754},
year={2006},
publisher={Elsevier}
}
@article{Heidenreich2013,
title={Forecasting the impact of heart failure in the United States a policy statement from the American Heart Association},
author={Heidenreich, Paul A and Albert, Nancy M and Allen, Larry A and Bluemke, David A and Butler, Javed and Fonarow, Gregg C and Ikonomidis, John S and Khavjou, Olga and Konstam, Marvin A and Maddox, Thomas M and others},
journal={Circulation: Heart Failure},
volume={6},
number={3},
pages={606--619},
year={2013},
publisher={Am Heart Assoc}
}


With your given information I could create a MWE, compiling without errors or warnings.

Because you gave us only code snippets I have to guess to get a compilable code. Please check my code for differences to yours. If there are differences, please add them into my code and add this changed code to your question.

With the following MWE (including the bib file with package filecontents)

\RequirePackage{filecontents}
\begin{filecontents*}{\jobname.bib}
@article{Ross2006,
failure care},
author={Ross, H and Howlett, J and Arnold, J Malcolm O and Liu, P and
O'Neill, BJ and Brophy, JM and Simpson, CS and Sholdice, MM and
Knudtson, M and Ross, DB and others},
volume={22},
number={9},
pages={749--754},
year={2006},
publisher={Elsevier},
}
@article{Heidenreich2013,
title={Forecasting the impact of heart failure in the United States a
policy statement from the American Heart Association},
author={Heidenreich, Paul A and Albert, Nancy M and Allen, Larry A and
Bluemke, David A and Butler, Javed and Fonarow, Gregg C and
Ikonomidis, John S and Khavjou, Olga and Konstam, Marvin A and
journal={Circulation: Heart Failure},
volume={6},
number={3},
pages={606--619},
year={2013},
publisher={Am Heart Assoc},
}
\end{filecontents*}

\documentclass[%
% final,
% 3p,times,twocolumn,
authoryear         % is passed to the natbib package, loaded by class
]{elsarticle}

\usepackage[utf8]{inputenc}

\usepackage{url}
\bibliographystyle{elsarticle-harv}
%\biboptions{authoryear} % Class option authoryear for elsearticle is the same!

\begin{document}
\section{Background}
Etc Etc Etc \citep{Heidenreich2013} and an estimated 500,000 Canadians \citep{Ross2006}.

\bibliography{\jobname}
\end{document}


I get no errors or warnings (the warning from package filecontents is okay!) and the resulting pdf:

There are two possibilitys for your error:

1. In my code is something missing (packages, options, code) that is causing the error or
2. in your BibTeX file is an error in one ore more entrys above the heidenreich entry.

Please check and report the results. Have a look in both files mwe.log and mwe.blg. If you get error messages please add the complete first error message to your question. Do you get warnings? Please add them too!

PS: Thanks to @mico for his comment. I added it to the mwe.

• +1. A minor comment: the instruction \biboptions{authoryear} is redundant as the option authoryear is passed from the document class to the natbib pacakge (which is loaded automatically by the elsarticle document class). – Mico Oct 13 '15 at 3:49