Annan, Francis, and Henry De-Graft Acquah. “A Regional Analysis of Corn Yield Models: Comparing Quadratic versus Cubic Trends”. Journal of Economics and Behavioral Studies 3, no. 6 (December 15, 2011): 395–401. Accessed October 25, 2026. https://amhinternational.com/jebs/article/view/2323-a-regional-analysis-of-corn-yield-models-comparing-quadratic-versus-cubic-trends.