Bibliographies from multiple .bib files

Question

I would like to use multiple .bib files for my article, such as file1.bib, file2.bib.

However, I would like my references not to be separated (such as "Primary sources", "Secondary sources", etc.). These bibliographies just need to be merged into one.

One way to do this is to copy-paste these .bib files into one .bib file, and this would solve the problem. However, I would like to keep it split into several .bib files, by topic (file1.bib contains articles on topic1, file2.bib contains articles on topic2, and so on).

I tried to do

\bibliographystyle{alpha}

\bibliography{file1}
\bibliography{file2}

but this just gives me the same bibliography twice!

Answer 1

The correct way to load multiple bib files is to use

\bibliography{file1,file2}

Note the lack of space between the comma and the files!

Answer 2

If you use the biblatex package and need to load multiple bib files, each bib file needs to be loaded separately via an \addbibresource instruction:

\addbibresource{file1.bib}
\addbibresource{file2.bib}

For more information, see section 3.6.1, "Resources", of the reference manual of the biblatex package.