Não informado. (1978). Rural Extension, Education and Training Abstracts. Commonwealth Agricultural Bureau.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Rural Extension, Education and Training Abstracts. Farnham Royal, Inglaterra: Commonwealth Agricultural Bureau, 1978.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Rural Extension, Education and Training Abstracts. Commonwealth Agricultural Bureau, 1978.
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