This is a gentle introduction to using some of the bibliography functionality available to LaTeX users beyond the BibTeX basics. This introduction won't be discussing how to create new styles or packages but rather how to use some existing ones. It is worth noting that Harvard, for example, is a citation style. It is associated with an alphabetical reference list secondarily ordered on date, but the only strictly defined element of Harvard style is the citation in author-date format.
The example data
The database used for my examples contains just the following
@article{Erdos65,
title = {Some very hard sums},
journal = {Difficult Maths Today},
author = {Paul Erd\H{o}s and Arend Heyting and Luitzen Egbertus Brouwer},
year = {1930},
pages = {30}
}
The limits of BibTeX styles
Using cite.sty and BibTeX makes it very easy to produce some bibliography styles. But author-date styles - for example the often mentioned, never defined "Harvard" - are not so easy. It's true that you can download some .bst files from CTAN that will handle some variants but using them is not always straightforward. This guide deals with Natbib a supplementary package that can access .bib files and has sophisticated functionality for producing custom or default author-year format citations and bibliographies as well as the numerical styles handled by BibTeX.
Natbib
Natbib is a package created by Patrick Daly as a replacement for the cite.sty package when author-date citation styles are required. Natbib provides three associated bibliography styles:
- plainnat
- abbrvnat
- unsrtnat
which correspond to the three styles available by default in BibTeX where you have a plain numbered style, an abbreviated numbered style and an unsorted numbered style.
Alongside these new styles is an extended set of citation commands to provide flexible citation formats. These are
\citet[]{}
and
\citep[]{}
each of which has a number of variants.
The Preamble
All Natbib styles require that you load the package in your document preamble. So, a skeleton LaTeX file with Natbib might look like this:
\documentclass[]{article}
\usepackage[round]{natbib}
\begin{document}
Document body text with citations.
\bibliographystyle{plainnat}
\bibliography{myrefs}
\end{document}
Options
Options available with Natbib can be specified in the brackets on the \usepackage command. Among them are:
| Option | Effect |
|---|---|
| round | () |
| square | [] |
| curly | {} |
| angle | <> |
| semicolon | separate citations with ; |
| colon | as semicolon |
| comma | separate with commas |
| authoryear | author-year citations |
| numbers | numeric citations |
| super | superscript citations |
| sort | multiple citations are ordered as in bibliography |
| sort&compress | as sort but number ranges are compressed and hyphenated |
| compress | number ranges are compressed and hyphenated but only where the 'natural' sort produces a continuous range |
| longnamesfirst | first citation is full author list and subsequent citations are abbreviated |
| sectionbib | allows multiple bibliographies in the same document |
| nonamebreak | forces all author names onto one line |
| merge | merges a citation with a previous citation |
| elide | elides any repeated elements in merged references |
| mcite | ignore merge |
Clearly some of these options require explanation but that will be achieved via examples below. For now, we just note that they can be passed through \usepackage[]{} in the preamble of your LaTeX file.
Citation
Basic Citation Commands
To cite with Natbib, use the commands \citet or \citep in your document. The "plain" versions of these commands produced abbreviated lists in the case of multiple authors but both have * variants which result in full author listings. We assume the use of the round option in these examples.
\citet and \citet*
The \citet command is used for textual citations, that is to say that author names appear in the text outside of the parenthetical reference to the date of publication. This command can take options for chapter, page numbers etc. Here are examples
| \citet{Erdos65} | produces | Erdős et al. (1965) |
| \citet[chapter 2]{Erdos65} | produces | Erdős et al. (1965, chapter 2) |
| \citet[pp. 10-12]{Erdos65} | produces | Erdős et al. (1965, pp. 10-12) |
| \citet[see][chap. 2]{Erdos65} | produces | Erdős et al. (see 1965, chap. 2) |
Here are the \citet* versions
| \citet*{Erdos65} | produces | Erdős, Heyting and Brouwer (1965) |
| \citet*[chapter 2]{Erdos65} | produces | Erdős, Heyting and Brouwer (1965, chapter 2) |
| \citet*[pp. 10-12]{Erdos65} | produces | Erdős, Heyting and Brouwer (1965, pp. 10-12) |
| \citet*[see][chap. 2]{Erdos65} | produces | Erdős, Heyting and Brouwer (see 1965, chap. 2) |
\citep and \citep*
The \citep command is used where the author name is to appear inside the parentheses alongside the date.
| \citep{Erdos65} | produces | (Erdős et al. 1965) |
| \citep[chapter 2]{Erdos65} | produces | (Erdős et al. 1965, chapter 2) |
| \citep[pp. 10-12]{Erdos65} | produces | (Erdős et al. 1965, pp. 10-12) |
| \citep[see][chap. 2]{Erdos65} | produces | (see Erdős et al. 1965, chap. 2) |
| \citep[e.g.][]{Erdos65} | produces | (e.g. Erdős et al. 1965) |
Here are the \citep* versions
| \citep*{Erdos65} | produces | (Erdős, Heyting and Brouwer 1965) |
| \citep*[chapter 2]{Erdos65} | produces | (Erdős, Heyting and Brouwer 1965, chapter 2) |
| \citep*[pp. 10-12]{Erdos65} | produces | (Erdős , Heyting and Brouwer 1965, pp. 10-12) |
| \citep*[see][chap. 2]{Erdos65} | produces | (see Erdős , Heyting and Brouwer, 1965, chap. 2) |
| \citep*[e.g.][]{Erdos65} | produces | (e.g. Erdős , Heyting and Brouwer, 1965) |
The Reference List
Having dealt with basic varieties of citation, we turn to the creation of the bibliography or reference list.
Inserting a correct and correctly formatted bibliography when using Natbib is no different than when using plain BibTeX. There are two essential commands -
\bibliography{mybibliographydatabase}
which LaTeX interprets as an instruction to read a bibliographic database file (eg myrefs.bib) and insert the relevant data here, and
\bibliographystyle{plainnat}
which specifies how the data are to be presented.
Above the three basic Natbib styles were mentioned as analogues of the partially homonymous styles in BibTeX. Let us imagine documents bearing citations as in the section about citation above. Here is, approximately, how these citations would appear in plainnat.
What more is there?
This covers the basic functionality provided by the package Natbib. It may not, of course, provide what you are looking for. If you don't find what you want here then you should probably next investigate harvard.sty which provides a slighly different set of author-date citation functions. Providing a gentle guide to harvard.sty is my next rainy day project.