Irawan, Diky, Hendra Grandis, and Prihadi Sumintadiredja. 2015. “Quasi-2D Resistivity Model from Inversion of Vertical Electrical Sounding (VES) Data Using Guided Random Search Algorithm”. Journal of Mathematical and Fundamental Sciences 47 (3):269-80. https://doi.org/10.5614/j.math.fund.sci.2015.47.3.5.