TARIGAN, R. E.; MUCHLISYAM; SINAGA, S. M.; ALFIAN, Z. 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 2020, 12, 249-252.