• Alston, Julian M., Michele C. Marra, Phillip G. Pardey and T.J. Wyatt (1998). “Research Returns Redux: A Meta-Analysis of the Returns to Agricultural R&D”. EPTD Discussion Paper No. 38. International Food Policy Research Institute, Washington, D.C.
• Cohen, W., R. Nelson and J. Walsh (1996). “Appropriability Conditions and Why Firms Patent and Why They Do Not in the American Manufacturing Sector.” Paper presented at the Conference on New Science and Technology Indicators for the Knowledge-Based Economy. OECD: Paris.
• DEFRA (2003). Productivity of UK Agriculture: Causes and Constraints. Accessed from http://statistics.defra.gov.uk/esg/reports/prodagri/
• Erratt, Judy, Konrad Sechley and Strathy Gowling (2000). “The European Biotechnology Directive and the Patentability of Higher Life Forms”. Canadian Biotechnology, 21 (5), pp. 22-27
• Evenson, R. E. and D. Gollen, eds. 2001. Crop Variety Improvement and Its Effect on Productivity: The Impact of International Agricultural Research. CABI: Wallingford, UK:
• Goldsmith, P. D. (2001). “Innovation, Supply Chain Control and the Welfare of Farmers.” American Behavioral Scientist, 44, pp. 1302-1326.
• Hayenga, M. L. (1998). “Structural Change in the Biotech Seed and Chemical Industrial Complex.” AgBioForum 1, pp. 43-55.
• Levin, R., A. Klevorick, R. Nelson and S. Winter (1987). “Appropriating Returns From Industrial Research and Development.” Brooking Papers on Economic Activity: Microeconomics, pp. 783-820.
• Morris, M. (Ed) (1998). Maize Seed Industry in Developing Countries. Lynne Rienner and CIMMYT, Mexico.
• OECD (2000). Economic Accounts for Agriculture –1999. Organization for Economic Co-operation and Development, Paris.
• Pakes, A.S. (1986). Patents as Options: Some Estimates of the Value of Holding European Patent Stocks. Econometrica, 54, pp. 755-784.
• RAFI (1997). Update: The Life Industry - 1997. Rural Advancement Foundation International, Canada. http://www.etcgroup.org.
• Rausser, G., S. Scotchmer, and L. Simon. (1999) "Intellectual Property and Market Structure in Agriculture". Paper presented at the Conference on "The Shape of the Coming Agricultural Biotechnology Transformation: Strategic Investment and Policy Approaches from an Economic Perspective" organised by the International Consortium on Agricultural Biotechology Research (ICABR), 17-18 June, Ravello, Italy.
• Schankerman, M and Ariel Pakes (1986). “Estimates of the Value of Patent Rights in European Countries During the Post 1950 period”. Economic Journal, 96 (384), pp. 1052-1076.
• Schankerman, M. (1998). “How Valuable is Patent Protection: Estimates by Technology Field.” Rand Journal of Economics, 29 (1),pp. 77-107.
• Sullivan, R.J. (1994). Estimates of the Value of Patent Rights in Great Britain and Ireland: 1852-1876. Economica, 16, pp. 37-58.
• Taylor, C. and Z. Silberstson (1973). The Economic Impact of the Patent System. Cambridge University Press, Cambridge.
• Teece, D. J. (Ed.) (1987) The Competitive Challenge: Strategies for Industrial Innovation and Renewal. Ballinger Publishing Company, Cambridge, Massachusetts.