total number of observations : 816
observation : regional
country : United States
data(Produc)
Baltagi, B. H. and N. Pinnoi (1995) Public capital stock and state productivity growth: further evidence, Empirical Economics, 20(2), pp. 351--359.
Munnell, A.H. (1990) Why has productivity growth declined? Productivity and public investment, New England Economic Review, pp. 3--22.