Não informado. (1951). Increasing understanding of public problems and policies. Farm Foundation.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Increasing Understanding of Public Problems and Policies. Chicago, Ill: Farm Foundation, 1951.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Increasing Understanding of Public Problems and Policies. Farm Foundation, 1951.
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