S. Bijaksana, I. Rusyanti, M. I. T. Taib, L. A. Pasasa, and A. S. Andreas, “The Use of GPR in Delineating an Iron Sand Boundary and the Determination of Its Electromagnetic Wave Velocity: A Case Study in Jepara, Central Java”, J. Eng. Technol. Sci., vol. 37, no. 2, pp. 77-90, Jan. 2014.