1. 2005 Report Card for America's Infrastructure
2. Why is infrastructure important?;David Aschauer;Is There a Shortfall in Public Capital Investment? Alicia H. Munnell,1990
3. Forthcoming. Capital Intensity in Canada and the United States;John R Baldwin;Canadian Productivity Review. Ottawa: Statistics Canada
4. Executive Order 13010: Critical Infrastructure Protection;Federation of American Scientists,1996