Sudarningsih, S., L. Maulana, S. Bijaksana, A. Hafidz, A. Pratama, W. Widodo, and I. Iskandar. “Magnetic Characterization of Sand and Boulder Samples from Citarum River and Their Origin”. Journal of Mathematical and Fundamental Sciences, vol. 49, no. 2, Oct. 2017, pp. 116-2, doi:10.5614/j.math.fund.sci.2017.49.2.2.