1. M.J. O'Neil (Ed.), The Merck Index, in: 13th ed., Merck & Co, NJ, 2001, p. 5262.
2. Clarke's Analysis of Drugs and Poisons,2011
3. Martindale, The Complete Drug Reference,2009
4. British Pharmacopoeia;British Pharmacopoeia,2012
5. D.J. Carini, J.V. Duncia, S.M. Wang, U.S. Patent No. 5,138,069, 1986.