John Kitchin <johnrkitchin <at> gmail.com> writes:

>
> It could also be you didn't specify a bibliographystyle.
>
> Try running M-x org-ref on the file. It checks that some things like that
are correct. Sometimes it is
> helpful to manually build the puff at the command line. Org hides a lot of
errors sometimes.
>

Thank you Prof. Kitchen,

Tried your suggestions with same result: references marked as [?] and no
bibliography generated.

/Nikolai