UK TeX FAQ -- question label usebibtex

### “Normal” use of BibTeX from LaTeX

To create a bibliography for your document, you need to perform a sequence of steps, some of which seem a bit odd. If you choose to use BibTeX, the sequence is:

First: you need a BibTeX bibliography file (a `.bib` file) — see “creating a BibTeX file”.

Second: you must write your LaTeX document to include a declaration of the ‘style’ of bibliography, citations, and a reference to the bibliography file mentioned in the step 1. So we may have a LaTeX file containing:

>     \bibliographystyle{plain}
>     ...
>     Pooh is heroic~\cite{Milne:1926}.
>     ...
>     Alice struggles~\cite{Carroll:1865}.
>     ...
>     \bibliography{mybooks}

Note: we have bibliography style plain, above, which is nearly the simplest of the lot: a sample text, showing the sorts of style choices available, can be found on Ken Turner’s web site: http://www.cs.stir.ac.uk/~kjt/software/latex/showbst.html

Third: you must process the file.

>     latex myfile

As LaTeX processes the file, the `\``bibliographystyle` command writes a note of the style to the `.aux` file; each `\``cite` command writes a note of the citation to the `.aux` file, and the `\``bibliography` command writes a note of which `.bib` file is to be used, to the `.aux` file.

Note that, at this stage, LaTeX isn’t “resolving” any of the citations: at every `\``cite` command, LaTeX will warn you of the undefined citation, and when the document finishes, there will be a further warning of undefined references.

Fourth: you must run BibTeX:

>     bibtex myfile

Don’t try to tell BibTeX anything but the file name: say `bibtex myfile.aux` (because you know it’s going to read the `.aux` file) and BibTeX will blindly attempt to process `myfile.aux.aux`.

BibTeX will scan the `.aux` file; it will find which bibliography style it needs to use, and will “compile” that style; it will note the citations; it will find which bibliography files it needs, and will run through them matching citations to entries in the bibliography; and finally it will sort the entries that have been cited (if the bibliography style specifies that they should be sorted), and outputs the resulting details to a `.bbl` file.

Fifth: you run LaTeX again. It warns, again, that each citation is (still) undefined, but when it gets to the `\``bibliography` command, it finds a `.bbl` file, and reads it. As it encounters each `\``bibitem` command in the file, it notes a definition of the citation.

Sixth: you run LaTeX yet again. This time, it finds values for all the citations, in its `.aux` file. Other things being equal, you’re done… until you change the file.

If, while editing, you change any of the citations, or add new ones, you need to go through the process above from steps 3 (first run of LaTeX) to 6, again, before the document is once again stable. These four mandatory runs of LaTeX make processing a document with a bibliography even more tiresome than the normal two runs required to resolve labels.

To summarise: processing to resolve citations requires: LaTeX; BibTeX; LaTeX; LaTeX.

This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=usebibtex