Williams, D. B. (1968). Agricultural extension : farm extension: Services in Australia, Britain and the united states of America. Melbourne U.Pr.
Chicago-čujuhus (17. p.)Williams, Donald B. Agricultural Extension : Farm Extension: Services in Australia, Britain and the United States of America. Carlton, Vic: Melbourne U.Pr, 1968.
MLA-čujuhus (9. p.)Williams, Donald B. Agricultural Extension : Farm Extension: Services in Australia, Britain and the United States of America. Melbourne U.Pr, 1968.
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