References
- Bureau of Economic Analysis (BEA), U.S. Department of Commerce. 1987 . Fixed Reproducible Tangible Wealth in the United States, 1925–85 , Washington, DC : Superintendent of Documents .
- Bureau of Economic Analysis (BEA), U.S. Department of Commerce. 1990 . Survey of Current Business , 70 ( 9 ) : 105 (September)
- Munnell , Alicia H. 1990 . Is There a Shortfall in Public Capital Investment! , Boston : Federal Reserve Bank of Boston . Conference Series No. 34
- U.S. Census Bureau. 1991 . Statistical Abstract of the United States, 1991