Não informado. (1978). Rural Extension, Education and Training Abstracts. Commonwealth Agricultural Bureau.
Chicago (17e ed.) BronvermeldingNão informado. Rural Extension, Education and Training Abstracts. Farnham Royal, Inglaterra: Commonwealth Agricultural Bureau, 1978.
MLA (8e ed.) BronvermeldingNão informado. Rural Extension, Education and Training Abstracts. Commonwealth Agricultural Bureau, 1978.
Let op: Deze citaties zijn niet altijd 100% accuraat.