Williams, D. B. (1968). Agricultural extension : farm extension: Services in Australia, Britain and the united states of America. Melbourne U.Pr.
Chicago Style (17. basım) AtıfWilliams, Donald B. Agricultural Extension : Farm Extension: Services in Australia, Britain and the United States of America. Carlton, Vic: Melbourne U.Pr, 1968.
MLA (9th ed.) AtıfWilliams, Donald B. Agricultural Extension : Farm Extension: Services in Australia, Britain and the United States of America. Melbourne U.Pr, 1968.
Uyarı: Bu alıntı herzaman %100 doğru olmayabilir..