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3. British Pharmacopoeia CD 1998, version 2, The Stationery Office Ltd., Norwich, 1998.
4. European Pharmacopoeia 1997, third edition, Convention on the Elaboration of a European Pharmacopoeia (European Treaty Series No.50), Strasbourg, 1996, pp. 748–749.
5. Simultaneous determination of ascorbic acid, caffeine and paracetamol in drug formulations by differential-pulse voltammetry using a glassy carbon electrode