1. Martindale, in: J.E.F. Reynolds (Ed.), The Extra Pharmacopoeia, 31st Edition, The Pharmaceutical Press, London, 1996.
2. P.A. Insel, in: A.G. Gilman, T.W. Rall, A.S. Nies, P. Taylor Goodman and Gilman’s (Eds.), The Pharmacological Basis of Therapeutics, 8th Edition, McGraw-Hill, New York, 1990 (Chapter 26).
3. The British Pharmacopoeia, Her Majesty’s Stationery Office, London, 1998.
4. The United States Pharmacopoeia, XXIV Revision, The National Formulary XIX Rockville, USP Convention, 2000.