Não informado. (1976). Quick bibliography series. National Agricultural Library, Department of Agriculture.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Quick Bibliography Series. Beltsville, Md: National Agricultural Library, Department of Agriculture, 1976.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Quick Bibliography Series. National Agricultural Library, Department of Agriculture, 1976.
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