South Dakota Agricultural Experiment Station. (1964). Economics pamphlet. Agricultural Experiment Station, South Dakota State University.
Lua i Stíl Chicago (17ú heag.)South Dakota Agricultural Experiment Station. Economics Pamphlet. Brookings, S.D.: Agricultural Experiment Station, South Dakota State University, 1964.
Lua MLA (8ú heag.)South Dakota Agricultural Experiment Station. Economics Pamphlet. Agricultural Experiment Station, South Dakota State University, 1964.
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