1. J. O. Maryadele, In: "An Encyclopedia of Chemicals, Drugs, and Biologicals. The Merck Index," 14th ed., Merck & Co., Inc., Whitehouse Station, NJ, USA (2006).
2. P. J. Taylor, B. G. Charles, R. Norris, P. Salm, and P. J. Ravenscroft, J. Chromatogr., 581, 152–l55 (1992).
3. The British Pharmacopoeia, Vol. I, HM Stationery office, London (2003).
4. R. T. Sane, R. V. Tendolkar, D. P. Gangal, K. D. Ladage, and R. M. Kothurkar, Indian J. Pharm. Sci., 51, 61–62 (1989).
5. K. Šlais and J. Šubert, J. Chromatogr. A, 191, 137–143 (1980).