6Jorge Fernandez-Cornejo: The Seed Industry in U.S. Agriculture: USDA, Economic Research Service, Agriculture Information Bulletin Number, 2004:786.
7Jorge Sanchez and Wu Xinping China People's Republic Planting seeds Annual 2006, USDA Foreign Agricultural Service, Gain Report Number CH6,2007 : 104.
8UNCTAD secretariat (2006) : Tracking the Trend towards Market Concentration: The Case of the Agricuhural Input Industry, United Nations Conference on Trade and Development 2006. www. unctad.org/TEMPLATES/Page. asp? inIthemID = 1931 &lang = 1.
9Graham Brookes et al. : Global hnpact of Biotech Crops: Socio - Economic and Environmental Effects in the First Ten Years of Commercial Use. AgBioForum, Volume 9, Number 3 - 2006 - Pages. 2006 : 139 - 151.
10Murray Fulton et al. (2001): Agricultural Biotechnology and Industry Structure. AgBioForum Volume 4, Number 2 - 2001:137 - 151.