Não informado. (1974). Journal of Rural Economics and Development. University of Ibadan, Department of Agricultural Extension Services.
Chicago-referens (17:e uppl.)Não informado. Journal of Rural Economics and Development. Ibadan, Nigeria: University of Ibadan, Department of Agricultural Extension Services, 1974.
MLA-referens (8:e uppl.)Não informado. Journal of Rural Economics and Development. University of Ibadan, Department of Agricultural Extension Services, 1974.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.