If you're thinking of multiple bibliographies tied to some part of your document (such as the chapters within the document), please see bibliographies per chapter.
For more than one bibliography, there are three options.
The multibbl package offers a very simple interface: you use
a command \newbibliography to define a bibliography "tag". The package
redefines the other bibliography commands so that each time you use any one
of them, you give it the tag for the bibliography where you want the
citations to appear. The \bibliography command itself also takes
a further extra argument that says what title to use for the resulting
section or chapter (i.e., it patches
\refname and \bibname in a
babel-safe way). So one might write:
\usepackage{multibbl}
\newbibliography{bk}
\bibliographystyle{bk}{alpha}
\newbibliography{art}
\bibliographystyle{art}{plain}
...
\cite[pp.~23--25]{bk}{milne:pooh-corner}
...
\cite{art}{einstein:1905}
...
\bibliography{bk}{book-bib}{References to books}
\bibliography{art}{art-bib}{References to articles}
(Note that the optional argument of \cite appears before the
new tag argument, and that the \bibliography commands may list
more than one .bib file - indeed all \bibliography commands
may list the same set of files.)
The \bibliography data goes into files whose names are
<tag-name>.aux, so you will need to run
after the first run of LaTeX, to get the citations in the correct place.bibtex bk bibtex art
The multibib package allows you to define a series of "additional topics", each of which comes with its own series of bibliography commands. So one might write:
\usepackage{multibib}
\newcites{bk,art}%
{References from books,%
References from articles}
\bibliographystylebk{alpha}
\bibliographystyleart{plain}
...
\citebk[pp.~23--25]{milne:pooh-corner}
...
\citeart{einstein:1905}
...
\bibliographybk{book-bib}
\bibliographyart{art-bib}
Again, as for multibbl, any \bibliography... command may
scan any list of .bib files.
BibTeX processing with multibib is much like that with multibbl; with the above example, one needs:
Note that, unlike multibbl, multibib allows a simple, unmodified bibliography (as well as the "topic" ones).bibtex bk bibtex art
The bibtopic package allows you separately to cite several
different bibliographies. At the appropriate place in your document,
you put a sequence of btSect environments (each of which
specifies a bibliography database to scan) to typeset the separate
bibliographies. Thus, one might have a file diss.tex containing:
\usepackage{bibtopic}
\bibliographystyle{alpha}
...
\cite[pp.~23--25]{milne:pooh-corner}
...
\cite{einstein:1905}
...
\begin{btSect}{book-bib}
\section{References from books}
\btPrintCited
\end{btSect}
\begin{btSect}[plain]{art-bib}
\section{References from articles}
\btPrintCited
\end{btSect}
Note the different way of specifying a bibliographystyle: if you want
a different style for a particular bibliography, you may give it as an
optional argument to the btSect environment.
Processing with BibTeX, in this case, uses .aux files whose names
are derived from the name of the base document. So in this example
you need to say:
bibtex diss1 bibtex diss2
There is also a command \btPrintNotCited, which gives the rest of
the content of the database (if nothing has been cited from the
database, this is equivalent to LaTeX standard \nocite{*}).
However, the real difference from miltibbl and
mltibib is that selection of what appears in each
bibliography section is determined in bibtopic by what's in
the .bib files.
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=multbib