Chaniago, Irawati, et al. “Sorghum (Sorghum Bicolor L. Moench) Early Growth in Response to Al Stress: In Search for Al-Tolerant Sorghum Genotypes”. International Journal on Advanced Science, Engineering and Information Technology, vol. 6, no. 1, Jan. 2016, pp. 6-9, doi:10.18517/ijaseit.6.1.597.