1. Gurudeep Chatwal, G.R. Anand, Instrumental Methods of Chemical Analysis, ed-5th, Himalaya Publishing House, New Delhi., PP.2.624-2.629, 2007.
2. Skoog D.A. Holler, F.G. Nieman., Principles of Instrumental Analysis, ed-5th, Thomson Brooks/Cole Asia Pvt. Ltd., Singapore, PP.4-7, 2004.
3. Indian Pharmacopoiea 2007, Govt. of India, Ministry of Health and Family Welfare, Delhi, Indian Pharmacopoeial Commission, Ghaziabad, 2007.
4. USP 32 NF 27, United States Pharmacopoeia, The United States Pharmacopoeial Convention, Rockville, MD, 2009.
5. Sweetman S C Martindale, The Complete Drug Reference. 34th Ed. London, Pharmaceutical Press, 2005.