1. MARTINDALE The Extra pharmacopoeia, J.E.F. Reynolds (Ed.) Pharmaceutical Press, London, 1996.
2. U.S.Pharmacopoeia USP XVII, United States Pharmacopoeial Convention Inc., 12601, Twinbrook Parkway Rockville, MD 20852.
3. A. Gordus, Analytical Chemistry, Schaum's Outline Series in Science, 1987, N.Y., p. 30