1. U.S. Department of Agriculture. Food Consumption. Prices, Expenditures. Supplement to 1975 Agricultural Economic Report No. 138, E.R.S., Washington, D.C., January 1977.
2. U.S. Department of Agriculture. National Food Situation. NSF-161, E.R.S., Washington, D.C., September 1977.
3. U.S. Department of Agriculture. State Farm Income Statistics. Supplement to Statistical Bulletin No. 576, E.R.S., September 1977.