“…They demonstrated the importance of the development of complementary activities with technological proximity in order to further support the existence of knowledge spillovers. Since then, many authors, such as Boschma and Iammarino (), Hartog, Boschma, and Sotarauta (), Boschma, Minondo, and Navarro (), Van Oort, Geus, and Dogaru (), Caragliu, De Dominicis, and De Groot (), Lazzeretti, Innocenti, and Capone (), and Firgo and Mayerhofer (), have been incorporating such concepts in order to evaluate the effects of economic externalities on regional economic performance.…”