T. Purba, E. M. Harahap, C. Hanum, and R. Rahmawaty, “Land Suitability Evaluation For Paddy , Corn and Soybean in Binangalom Watershed Toba Samosir District North Sumatera”, IJSBAR, vol. 33, no. 1, pp. 131–144, Apr. 2017, Accessed: Sep. 12, 2025. [Online]. Available: https://www.gssrr.org/JournalOfBasicAndApplied/article/view/7201