Hayati, Zinatul, et al. “In Vitro Antibacterial Activity of Curcumin and Protocatechuic Acid Against Extended-Spectrum β-Lactamase–Producing Klebsiella Pneumoniae Isolated from Chronic Cough Sputum”. Journal of Society Medicine, vol. 5, no. 1, Jan. 2026, pp. 14-22, doi:10.71197/jsocmed.v5i1.258.