[latex] How to order citations by appearance using BibTeX?

By default (using the plain style) BibTeX orders citations alphabetically.

How to order the citations by order of appearance in the document?

I use natbib in combination with bibliographystyle{apa}. Eg:

\begin{document}

The body of the document goes here...

\newpage

\bibliography{bibliography} % Or whatever you decided to call your .bib file 

\usepackage[round, comma, sort&compress ]{natbib} 

bibliographystyle{apa}
\end{document}

Change

\bibliographystyle{plain}

to

\bibliographystyle{ieeetr}

Then rebuild it a few times to replace the .aux and .bbl files that were made when you used the plain style.

Or simply delete the .aux and .bbl files and rebuild.

If you use MiKTeX you shouldn't need to download anything extra.

The datatool package offers a nice way to sort bibliography by an arbitrary criterion, by converting it first into some database format.

Short example, taken from here and posted for the record:

\documentclass{article}

\usepackage{databib}

\begin{document}
% First argument is the name of new datatool database
% Second argument is list of .bib files
\DTLloadbbl{mybibdata}{acmtr}
% Sort database in order of year starting from most recent
\DTLsort{Year=descending}{mybibdata}
% Add citations
\nocite{*}

% Display bibliography
\DTLbibliography{mybibdata}
\end{document}

Add this if you want the number of citations to appear in order in the document they will only be unsorted in the reference page:

\bibliographystyle{unsrt}

Just a brief note - I'm using a modified version of plain.bst sitting in the directory with my Latex files; it turns out having sorting by order of appearance is a relatively easy change; just find the piece of code:

...
ITERATE {presort}

SORT
...

... and comment it - I turned it to:

...
%% % avoid sort:
%% ITERATE {presort}
%%
%% SORT
...

... and then, after running bibtex, pdflatex, pdflatex - the citations will be sorted by order of appearance (that is, they will be unsorted :) ).

Cheers!

EDIT: just realized that what I wrote is actually in the comment by @ChrisN: "can you edit it to remove the SORT command" ;)

You answered your own question---unsrt is to be used when you want references to ne listed in the order of appeareance.

But you might also want to have a look at natbib, an extremely flexible citation package. I can not imagine living without it.

I'm a bit new to Bibtex (and to Latex in general) and I'd like to revive this old post since I found it came up in many of my Google search inquiries about the ordering of a bibliography in Latex.

I'm providing a more verbose answer to this question in the hope that it might help some novices out there facing the same difficulties as me.

Here is an example of the main .tex file in which the bibliography is called:

\documentclass{article}
\begin{document}

So basically this is where the body of your document goes.

``FreeBSD is easy to install,'' said no one ever \cite{drugtrafficker88}.

``Yeah well at least I've got chicken,'' said Leeroy Jenkins \cite{goodenough04}.

\newpage
\bibliographystyle{ieeetr} % Use ieeetr to list refs in the order they're cited
\bibliography{references} % Or whatever your .bib file is called
\end{document}

...and an example of the .bib file itself:

@ARTICLE{ goodenough04,
AUTHOR    = "G. D. Goodenough and others", 
TITLE     = "What it's like to have a sick-nasty last name",
JOURNAL   = "IEEE Trans. Geosci. Rem. Sens.",
YEAR      = "xxxx",
volume    = "xx",
number    = "xx",
pages     = "xx--xx"
}
@BOOK{ drugtrafficker88,
AUTHOR    = "G. Drugtrafficker", 
TITLE     = "What it's Like to Have a Misleading Last Name",
YEAR      = "xxxx",
PUBLISHER = "Harcourt Brace Jovanovich, Inc."
ADDRESS   = "The Florida Alps, FL, USA"
}

Note the references in the .bib file are listed in reverse order but the references are listed in the order they are cited in the paper.

More information on the formatting of your .bib file can be found here: http://en.wikibooks.org/wiki/LaTeX/Bibliography_Management

The best I came up with is using the unsrt style, which seems to be a tweaked plain style. i.e.

\bibliographystyle{unsrt}
\bibliography{bibliography}

However what if my style is not the default?

with unsrt the problem is the format. use \bibliographystyle{ieeetr} to get refences in order of citation in document.

If you happen to be using amsrefs they will override all the above - so comment out:

\usepackage{amsrefs}

I often use the bibliography style natbib because it supplies quite complete set of formats as well as tags for us.