Idrus, Arifudin, et al. “Geology and Characteristics of Pb-Zn-Cu-Ag Skarn Deposit at Ruwai, Lamandau Regency, Central Kalimantan”. Indonesian Journal on Geoscience, vol. 6, no. 4, Dec. 2011, pp. 191-0, doi:10.17014/ijog.6.4.191-201.