1. 12 Nelson K. , Case J. , Harder D. , and Smoot R. 2002. Comparison of natto, clear hilum, sprout, and roundup ready® soybean grain yield. Available at Web site http://aes.missouri.edu/greenley/research/soy1112.stm (accessed 4 October 2009).
2. 10 American Agricultural Economics Association. 2000. Commodity Costs and Returns Estimation Handbook. A Report of the AAEA Task Force on Commodity Costs and Returns, Ames, IA.
3. 13 Streff N. and Dobbs T. 2004. Organic and conventional grain and soybean prices in the northern Great Plains and upper Midwest: 1995–2003. Econ. Pamphlet 2004-1, Economics Department, South Dakota State University.
4. 3 The Organic and Non-GMO Report. 2007. USDA Organic Report: Soybean Acreage Down, Corn Acreage Up. Available at Web site http://www.non-gmoreport.com/articles/feb07/organic_corn_soybeans.php (accessed 4 October 2009).
5. 15 U.S. Department of Agriculture, Agricultural Marketing Service. 2008. USDA Market News: Upper Midwest Organic Grain and Feedstuffs Report. Available at Web site http://www.ams.usda.gov/mnreports/nw_gr113.txt (accessed 4 October 2009).