8Keller W., International Trade, Foreign Direct Investment, and Technology Spillovers. Handbookof the Economics of In- novation, Hall B H,Rosenberg N, Amsterdam:Elsevier, 2010, PP793-829.
9Keller W., Geographic localization oflntemationalTechnology Diffusion. American Economic Review, 2002, ( 1 ).
10Moreno R, Paci R, Usai S, Spatial spillovers and innovation activity in European regions. Environment and Planning A, 2OO5, (10).