Trongkongsin, K. “Potential Production of Four Tropical Pasture Grass Species of Nitrogen Fertilizer after Defoliztions”. Thai Agricultural Research Journal, vol. 9, no. 3, Sept. 1991, pp. 173-85, https://li01.tci-thaijo.org/index.php/thaiagriculturalresearch/article/view/242395.