R. E. TARIGAN, MUCHLISYAM, S. M. SINAGA, and Z. ALFIAN, “DEVELOPMENT AND VALIDATION OF DOUBLE DIVISOR RATIO SPECTRA DERIVATIVE SPECTROPHOTOMETRY METHOD FOR TERNARY MIXTURE OF DEXTROMETHORPHAN HYDROBROMIDE, DOXYLAMINE SUCCINATE AND PSEUDOEPHEDRINE HYDROCHLORIDE IN TABLET DOSAGE FORM”, Int J App Pharm, vol. 12, no. 6, pp. 249–252, Nov. 2020.