1. Udenfriend S., Fluorescence Assay in Biology and Medicine, Vol. II, chapter 13. New York: Academic Press. 1969.
2. Windholz M. (editor), The Merck Index, 9th ed., no. 4470. New York: Rahway. Merck & Co. 1976.
3. Poethke W., Schwarz Ch., Gerlach H., Planta Med.18, 303 (1970).
4. Poindexter E. H.,Jr.,Carpenter R. D., Chem. & Ind. (London)1962, 176.
5. Izmailov N. A.,Schraiber M. S., Farmatsiya & Farmakol.1938, 8; Chem. Abstr.34, 8178 (1940).