1. The Extra Pharmacopoeia Martindale, 30th ed., The Pharmaceutical Press, London, 1993, pp. 1418, 1385.
2. Japan Pharmaceutical Information Center, Drugs in Japan, Ethical Drugs, Yakugyo Jiho, Tokyo, 1992, pp. 646.
3. The United States Pharmacopeia and the National Formulary, United States Pharmacopeial Convention, Rochville, 1995, pp. 2314, 2262.
4. British Pharmacopoeia, vol. I, HMSO, London, 1993, pp. 652.
5. High-performance liquid chromatographic determination of major organic acids in apple juices and ciders