Não informado. (1960). Agriculture in Northern Ireland. Department of Agriculture.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Agriculture in Northern Ireland. Belfast, Irlanda: Department of Agriculture, 1960.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Agriculture in Northern Ireland. Department of Agriculture, 1960.
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