knowledge spillovers = refer to the positive externalities that firms receive in terms of knowledge from the environment in which it operates.
Cited in this study: http://ideas.repec.org/p/wiw/wiwrsa/ersa02p042.html
From the Wikipedia:
"Knowledge spillover is an exchange of ideas among individuals. In knowledge management economics, a knowledge spillover is a non-rival knowledge market externality that has a spillover effect of stimulating technological improvements in a neighbor through one's own innovation. Such innovations often come from specialization within an industry." (http://en.wikipedia.org/wiki/Knowledge_spillover)
Also see :