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 January 16, 2026. https://gssrr.org/JournalOfBasicAndApplied/article/view/4020