1. The British Pharmacopoeia. Her Majesty’s Stationary Office, London, 2007.
2. Martindale: The Extra Pharmacopoeia, 34th edn. The Complete Drug References. The Pharmaceutical Press, London, 2005.
3. The United States Pharmacopeia, 32th edn., National Formulary 27. United States Pharmacopeial Convention Inc., Rockville, MD, 2009.