“A HYDROGEOLOGY RESEARCH BY USING SCHLUMBERGER GEO-ELECTRIC METHOD IN DISTRICT HAMPARAN PERAK, DELI SERDANG, NORTH SUMATERA”. Proceeding International Conference (SBC-MEA) 2016, vol. 1, no. 1, Maret 2016, hlm. 156-61, https://jurnal.abulyatama.ac.id/index.php/mea2016/article/view/579.