1. Human Motives in Farming;Ashby;Welsh Journal of Agriculture,1926
2. The Nuffield Devon Farm Project;Morris;Journal of Agricultural Economics,1964
3. 4. Paarlberg, D. Public Policy and the Social Sciences. Address to third World Congress of Rural Sociology, Baton Rouge, Louisiana, 1972.
4. 5. Mitchell, W. C. ‘Empirical Research and the Development of Economic Science’. In: Economic Research and the Development of Economic Science and Public Policy, National Bureau of Economic Research, New York, pp. 16-17.