BibTeX isn't working; my \cite are showing up as question marks (?)

This can happen for a number of reasons:

• Have you used any \cite commands in your document? Only bib entries that have been \cite in the main text will appear in the bibliography list.
• Did you specify the correct .bib file name (without extensions) for \bibliography{...}? It's case sensitive, so watch out for typos.
• Have you specified the bibliography style with a \bibliographystyle{...}? If the style isn't a standard one that comes with TeX Live, you will need to upload the .bst file to your project.
• You may have a syntax error in your .bib file that's preventing bibtex from parsing it correctly. If so, there should be some information about this in the warning messages; fix them accordingly and bibtex should be able to read them again.

For more information about BibTeX, take our free online interactive tutorial, or take a look at this video tutorial and Wikibook articles.