Juliani R, Sembiring T, Sitepu M, Motlan . Geophysical Study for Discovering The Missing of Lau Ketuken from The Surface at Sulkam Village. IJSBAR. 2015;22(1):360-366. Accessed September 13, 2025. https://www.gssrr.org/JournalOfBasicAndApplied/article/view/4020