Gunawardana, A. M. T., Wickramasinghe, M. L., & Abeyratne, S. (1980). Farmers' knowledge and perception of improved technology: A study of five farming systems. Agrarian Research and Training Institute.
Chicago-viite (17. p.)Gunawardana, A. M. T., M. L. Wickramasinghe, ja S. Abeyratne. Farmers' Knowledge and Perception of Improved Technology: A Study of Five Farming Systems. Colombo: Agrarian Research and Training Institute, 1980.
MLA-viite (8. p.)Gunawardana, A. M. T., et al. Farmers' Knowledge and Perception of Improved Technology: A Study of Five Farming Systems. Agrarian Research and Training Institute, 1980.
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