V. D. Dewaantari, S. Setyabudi, and K. Ismiyatin, “Antioxidant Potential of Epigallocatechin-3-gallate, Ascorbic Acid, and Sodium Ascorbate in Solution and Gel Forms by 2,2-diphenyl-1-picrylhydrazyl (DPPH) Assay”, CDJ, vol. 11, no. 1, pp. 19–23, Jun. 2021.