Firdaus, Irvan Maulana, et al. “The Study of Pineapple Peel (Ananas Comosus L.) Waste Based-Electrolyte Medium: A Simple Experiment Design for the Students”. Walisongo Journal of Chemistry, vol. 2, no. 2, Dec. 2019, pp. 89-96, doi:10.21580/wjc.v2i2.6029.