Ghulamahdi, M., R. Agustian, I. Lubis, M. Murdianto, and P. Taylor. “Growth, Productivity and Land Equivalent Ratio of Soybean-Corn Intercropping on the Different Potassium and Husk Ash Dose under Saturated Soil Culture on Tidal Swamp”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 36, no. 7, Dec. 2017, pp. 170-82, https://www.gssrr.org/index.php/JournalOfBasicAndApplied/article/view/8175.