Sakhunkhu, S., and S. Faungfupong. “Effects of Tillage Systems and Methods of Weed Control on Grain Yield and Some Agronomic Characteristics of Corn”. Agriculture and Natural Resources, vol. 19, no. 2, May 1985, pp. 85-91, https://li01.tci-thaijo.org/index.php/anres/article/view/242435.