1. M. Siregar and Sumaryanto. 2003. Estimating soybean production efficiency in irrigated area of Brantas River basin. Indonesian Journal of Agricultural Science 4(2): 33–39
2. O. Sadeghipour amd S. Abbasi. 2012. Soybean response to drought and seed inoculation. World Appl. Sci. J. 17(1): 55–60
3. B. Wiebold. 2012. Comparison of the 2012 drought to other drought for yield reductions (Part 2: soybean). Integrated Pest Crop Management 2(11): 113–114 http://ipm.missouri.edu/IPCM/archive/2012/v22n11.pdf [19 Oct 2015]
4. T. Oya, A.L. Nepomuceno, N. Neumaier, J.R.B. Farias, S. Tobita and O. Ito. 2004. Drought tolerance characteristics of Brazilian soybean cultivars – Evaluation and characterization of drought tolerance of various Brazilian soybean cultivars in the field –. Plant Prod. Sci. 7(2): 129–137
5. Suhartina and D.M. Arsyad. 2005. Tolerance of varieties and soybean lines to drought stress. National Workshop: Increased Production of Legumes and Tuber Crops to Support Self-Reliance of Food. (in bahasa Indonesia)