U. R. Irfan, I. Nur, and M. Kasim, “Hydrothermal Alteration Mineralogy Associated with Gold Mineralization in Buladu Area, Gorontalo, Northern Sulawesi, Indonesia”, Int. J. Adv. Sci. Eng. Inf. Technol., vol. 7, no. 6, pp. 2244–2250, Dec. 2017.