D. Susanti, N. Farid, I.N. Kantun, Suwarno and Shao-Hui Zheng, Totok A.D.H., Suwarto, A. Riyanto,. 2011. “Variability of Grain Protein Content in Improved Upland Rice Genotypes and Its Response to Locations”. Electronic Journal of Plant Breeding 2 (2), 200-208. https://ejplantbreeding.org/index.php/EJPB/article/view/1002.