Poungprakho, Krontong. “Competition in Maize by Annual Weeds І Annual Variability in competition Effects due to Rainfuall an dNitrogen Fertilizer”. Thai Agricultural Research Journal 8, no. 2 (May 1, 1990): 28–33. accessed September 30, 2026. https://li01.tci-thaijo.org/index.php/thaiagriculturalresearch/article/view/242413.