Natbib – Advanced Citations
While citations and references were already covered in part 2 of the course, the natbib package extends BiBTeX’s capabilities and offers more flexibility in customizing LaTeX bibliographies by including new bibliography styles and extending the \cite command. The structure of the bibliography file (.bib) used by natbib remains the same as in BibTeX.
Same as in BiBTeX, the bibliography style is set using the \bibliographystyle command. Useful styles include agsm which sets Harvard-like references (the citation style officially used by the PAIS department), as well as plainnat and abbrvnat (which are similar, but the latter uses first name initials instead of full names). By default, some styles (such as apalike or agsm) use round parentheses, while others (like plainnant) use round brackets. This can be changed by loading the natbib with the round option (\usepackage[round]{natbib}) which overrides the default style parentheses to be round or the square option, which does the opposite. Note that when changing the bibliography style in a file once rendered, you need to delete the .bbl auxiliary file which appears in the same folder as your rendered document.
Natbib also implements multiple versions of the citation command. Rather than using \cite as in BiBTeX, the simplest form of bibliography citation is \citep. \citet is a second alternative, which inserts the author’s surname without parentheses, followed by the publication year enclosed in parentheses. This allows you to cite a resource when using the author’s surname in the sentence, as demonstrated in the example.
\documentclass{article}
\usepackage{natbib}
\bibliographystyle{agsm}
\begin{document}
\citet{schadkeetal2007} conducted an experiment demonstrating that prolonged deliberation about politics amongst like-minded voters results in amplified ideological polarization.
Experiments have shown that prolonged deliberation about politics amongst like-minded voters results in amplified ideological polarization \citep{schadkeetal2007}.
\bibliography{my_bibliography}
\end{document}Both \citep and \citet have their alternative versions - \citealp and \citealt, which remove the parentheses entirely. The difference between \citealp and \citealt is that the latter separates the author’s name and publication year with a comma. This does not apply to the agsm bibliography style, which uses no comma between author’s surname and year – in this case, \citealp and \citealt are equivalent.
Adding an asterisk * at the end of each natbib’s citation command overrides the default et al. abbreviation commonly used in citations of resources with multiple authors and uses the names of all authors instead (this is not supported in some styles, such as apalike). Using the square brackets allows you to add prefixes and suffixes in the citation. So, when using \citep[option1][option2]{resource}, the option1 will be inserted before and option2 after the citation content (see example). Finally, using the \citetext command you can join multiple natbib citations and add your comments in between them, as shown in the example.
\documentclass{article}
\usepackage{natbib}
\bibliographystyle{agsm}
\begin{document}
Experiments have shown that prolonged deliberation about politics amongst like-minded voters results in amplified ideological polarization \citep*[see][pp.~920]{schadkeetal2007}. This undermines the applicability of theoretical models proposed by proponents of deliberative democracy \citetext{see \citealp{ackermanfishkin2004}, see also \citealp{cohen1989}}.
\bibliography{my_bibliography}
\end{document}Table 4 summarizes the functionality of different citation commands in Natbib. Check out the .tex file used to produce the table – it uses the listings package to cite LaTeX code inside of a LaTeX document.
| Command | Result |
|---|---|
| \citep{cohen1989} | (Cohen, 1989) |
| \citet{cohen1989} | Cohen (1989) |
| \citep[see][p. 920]{cohen1989} | (see Cohen 1989, p. 920) |
| \citealp{cohen1989} | Cohen, 1989 |
| \citealt{cohen1989} | Cohen 1989 |
| \citet*{schadkeetal2007} | Schadke, Sunstein & Hastie (2007)[1] |