  This paper analyses the influence of geographic distance on knowledge flows,
measured through citations to scientific publications. Previous works using the
same approach are limited to single disciplines. In this study, we analyse the
Italian scientific production in all disciplines matured in the period
2010-2012. To calculate the geographic distances between citing and cited
publications, each one is associated with a "prevalent" territory on the basis
of the authors' affiliations. The results of the application of a gravity
model, estimated using ordinary least squares regression, show that despite the
spread of IT, geographic distance continues to be an influential factor in the
process of knowledge flows between territories. In particular, the analysis
reveals that the effect of geographic distance on knowledge flows is
significant at the national level, not negligible at the continental level, but
completely irrelevant at the intercontinental level.
