Using Bibliographies and Citations

References live in a separate file ending in .bib. Each entry has a key you use to cite it — king2021 below:

@article{king2021,
  author  = {King, Gary},
  title   = {A Theory of Statistical Inference},
  journal = {Political Analysis},
  year    = {2021},
}

Add that file to your Overleaf project, either by uploading it or with New File. Then cite the key in your text, and ask for the bibliography where you want it printed:

As shown elsewhere \cite{king2021}, ...

\bibliographystyle{plain}
\bibliography{references}   % the .bib file's name, without .bib

Overleaf runs the extra compilation passes that citations need, so recompiling once is enough.

If you keep your references in Zotero, Mendeley or EndNote, you can export a .bib file and upload it. Overleaf can also link a Zotero or Mendeley library so the file updates by itself; see Overleaf’s documentation for how to connect one.