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The closing circle : nature, man, and technology
Commoner, Barry, (1971)
Studium von Düngungs- und agrikulturchemischen Fragen in den USA
Giesecke, Werner, (1956)
The pesticide problem : an economic approach to public policy
Headley, Joseph Charles, (1967)
An Analysis of agricultural co-operation in England
Knapp, Joseph G., (1965)
An appraisement of agricultural cooperation in Ireland
Knapp, Joseph G., (1964)
Are cooperatives good business?
Knapp, Joseph G., (1957)