Mahardianti, M., S. Septha Kharisma, R. Wati, and Y. Affandi. “Biopolymer Gel from Pineapple Peel (Ananas Comosus) Waste-Based Gel With Sodium Chloride (NaCl) for Optimizing Electrocardiogram (ECG) Signal Recording”. Journal of Energy, Material, and Instrumentation Technology, vol. 7, no. 1, Mar. 2026, pp. 26-35, doi:10.23960/jemit.386.