This paper analyzes the evolution of labor productivity disparities among 145 European regions over 1975-2000 according to the concepts of sigma- and beta-convergence and emphasizes the importance of including both spatial effects and a disaggregated analysis at a sectoral level.
Link
http://econpapers.repec.org/scripts/redir.pl?u=http%3A%2F%2Fwww.ersa.org%2Fersaconfs%2Fersa05%2Fpapers%2F191.pdf;h=repec:wiw:wiwrsa:ersa05p191