# Can I nest bibliography files into one another?

I make the bibliography for a manuscript with pdfLaTeX and bibTeX with a call

``````\bibliographystyle{unsrtnat}
\bibliography{path/list1,path/list2,path/list3}
``````

However, I realise that the some articles listed in list2 and list3 could be seen as a subsets of list1, or perhpas there are duplicates, and so on. A little tidying up is in order.

In the body of the text I make ample use of the `\input{}` construct for nesting tex files one into another. I was then thinking that nesting bib files would help me organize my bibliography better. I could express a hierarchy of topics modularly inside one main bib file. I made a naive attempt of nesting in a bib file in the tex way, but to no effect.

Is it possible to nest bib files in a similar way tex file do? If so, would someone please give tips and directions?

## 1 Answer

No, you can only append `.bib` files --- they are flat files by design (at least... I think!), although they have some minimal expansion/macro capability(1).

The best option is using some tidying applications, like `bibexport` or JabRef. Several options are listed in the answers to Cleaning up a .bib file

Note (1): for example you can say at the start of a `.bib` file:

``````@string{ESP = {\selectlanguage{spanish}}}
``````

and then use it as

`````` title = ESP #  {Dictamen del grado de coincidencia estructural ...}
``````
• As the chance arises, would you mind it to point in the direction of resources on the minimal expansion/macro capabilities? – XavierStuvw Feb 15 '20 at 20:55