The authors survey various types of GMO (genetically modified organism) corn and soybeans, including both pest-resistant and herbicide-resistant varieties, and then evaluate the extent to which farmers have begun to use GMO crops. Figures cited include percentages of acres planted with GMO crops, as well as comparisons of non-GMO versus GMO yields.
Babcock, Bruce A.; Duffy, Michael D.; and Wisner, Robert N., "Availability and Market Penetration of GMO Corn and Soybeans" (1999). CARD Briefing Papers. 14.