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Challenging the populist perspective : rural people's knowledge, agricultural research and extension practice
Scoones, Ian, (1993)
A century of productivity change in U.S. agriculture : an analysis of the role of invention, research and extension
Evenson, Robert E., (1978)
Persistence pays : U.S. agricultural productivity growth and the benefits from public R&D spending
Alston, Julian Mark, (2010)