# No comma between multiple authors in bibliography

I am trying to write a paper and at the bibliography I have several titles which contain multiple authors. I want a comma to appear between them, but even if in the bib file I write the authors with comma between them, in the pdf the comma does not appear. I am trying to do this using natbib. A friend sent me a paper which uses natbib and when I compiled it the comma appeared, but the same code does not work in my paper.

This is my paper:

\documentclass[a4paper,10pt]{report}
\usepackage[round]{natbib}
\usepackage[utf8x]{inputenc}
\usepackage{hyperref}

\title{Title}
\author{Author}

\date{}

\begin{document}
\maketitle
\begin{abstract}
Abstract
\end{abstract}

\section{Introduction}
\cite{williamson}

\bibliographystyle{plainnat}
\bibliography{bibliography}
\end{document}


And this is the entry from my bibliography.bib file:

@Book{williamson,
author={David P Williamson, David B Shmoys},
year = {2010},
title = {The Design of Approximation Algorithms},
publisher = {Cambridge University Press},
}


The way described in Ingmar's answer is the preferred one, but you don't get a separating comma between authors when you have only two of them.

I would follow that way, but if you really want a comma to separate them, you have to enclose the comma in braces, so that BibTeX considers it as normal text, i.e.

@Book{williamson,
author={David P Williamson{,} David B Shmoys},
year = {2010},
title = {The Design of Approximation Algorithms},
publisher = {Cambridge University Press},
}


Output

• Thank you! It worked. I really wanted to know how to place a comma between the authors – Jessy09 Dec 9 '13 at 16:05
• @Jessy09 -- Bear in mind that while this solution may be instructive and useful for this particular case, it cannot be recommended (as karlkoeller knows) in general: hard-coding a , into your author fields will make it impossible to use this .bib file for other projects that require a different approach to separating multiple authors or editors. You'd need to go through an delete all the {,} at the very least in order to get BibTeX to work. In the long-term, Ingmar's solution is better. The .bib file is just a database, and the corresponding .bst should determine the output. – jon Dec 9 '13 at 16:25
• Thank you. I will remember that; I accepted karlkoeller's answer because it was the answer I needed for my question, but I think that in the end I will stick with Ingmar's solution – Jessy09 Dec 9 '13 at 17:03

Authors are cited Lastname, First. Use "and" with multiple authors, like so:

@Book{williamson,
author={Williamson, David P and Shmoys, David B},
year = {2010},
title = {The Design of Approximation Algorithms},
publisher = {Cambridge University Press},
}

• But if I still want a comma to appear instead of the word and? – Jessy09 Dec 9 '13 at 15:57
• Have you tried it? This just concerns the input format of your .bib file, not the actual output. Just choose an appropriate style. – Ingmar Dec 9 '13 at 16:00
• Yes, I tried it. I will keep in mind how to write the authors, but I was just curious about how to separate them using a comma – Jessy09 Dec 9 '13 at 16:07