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2. “The Merck Index”, 11th Edn., p. 1324 (1989).
3. “Martindale” The Extra Pharmacopoeia,1989
4. “The United States Pharmacopoeia” 22nd Edn p. 1236 United States Pharmacopeial Convention, Inc., 12601 Twinbrook Parkway, Rockville MD 20852.
5. “The British Pharmacopoeia”,1980