#2470 Texstudio with Jabref: the reference is [?] instead of being properly presented

[aaron]

Hi, everyone,
I am new Texstudio user, when I try to use the bibliograpy in the texstudio, for some reason, it can only shows[?] instead of the reference. the warning is "WARN - No data sources defined! ", and the log shows that:"There were undifined references". I put the \bibliography{bibfile name} and \bibliographystyle{IEEE} before the begin{document}, but seems it doesn't work. Also, I am using mac laptop, I don't know wheter I have to do anyother setting.

Could someone help me to fix that? Thanks a lot!