1. Reynolds, J.E.F., Martindale: The Extra Pharmacopoeia, London: The Pharmaceutical Press, 1996, 31st ed.
2. The United States Pharmacopoeia XXI, National Formulary 19, Rockville: USP Convention, 1984.
3. British Pharmacopoeia, London: Her Majesty’s Stationary Office, 1988, vol. 1.
4. Bryant, R., Mantle, D.E., Timma, D.L., and Yoder, D.S., J. Pharm. Sci., 1968, vol. 57, no. 4, p. 658.
5. Cevdet, D. and Richard, G.B., Analyst, 1998, vol. 123, no. 2, p. 181.