"Changes in the Definition of Poverty," from Characteristics of the Population Below the Poverty Level: 1980" (P60-133) [PDF - 8M]
Describes technical adjustments to the poverty measure made by a federal interagency committee in 1980-1981.
OMB Statistical Policy Directive 14 (1978)
The Office of Management and Budget's directive establishing the official poverty measure for federal agencies to use in their statistical work.
The Measure of Poverty (1976)
A series of technical papers about poverty measurement performed for the Poverty Studies Task Force of the Federal Interagency Committee on Education.
Family Food Plans and Food Costs (1962) [PDF - 9.5M]
Includes the Economy Food Plan, used by Orshansky to develop poverty thresholds.