Possible Duplicate:
Question mark instead of citation number
I tried to add an existing BibTeX bibiography to my LyX document; it works fine when I add citations inside my document. But after compiling it, references are displayed as '?' in the PDF document and the bibliography list is not included.
xampl), add a citation and then compile with pdflatex, does it still not work? If so, I would perhaps ask on the LyX Users mailing list. Not that there's anything wrong with asking here, but I'm afraid there aren't many experts on LyX around, so for some questions I would guess that there's a better chance of getting an answer on the mailing list. – Torbjørn T. Oct 26 '12 at 06:01