Sudibyo, S., L. Hermida, and P. A. . Reswari. “Optimization of Electrometal - Electrowinning Cobalt Process from the Slag of Nickel Pig Iron (NPI)”. Journal of Materials Science and Applied Energy, vol. 10, no. 2, Apr. 2021, pp. 49-57, https://ph01.tci-thaijo.org/index.php/jmsae_ceae/article/view/242741.