Charles, I. (1970). The social security program in the United States (2d ed.). Appleton-Century-Crofts.
Παραπομπή Chicago StyleCharles, I. The Social Security Program in the United States. 2d ed. New York: Appleton-Century-Crofts, 1970.
Παραπομπή MLACharles, I. The Social Security Program in the United States. 2d ed. Appleton-Century-Crofts, 1970.
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