1. R. F. Doerge (ed.),Wilson and Gisvold's Text book of Organic Medicinal and Pharmaceutical Chemistry, 8th Ed., Lippincott, Philadelphia, 1982, pp. 190, 191.
2. A. C. Bratton, F. K. Marshall,J. Biol. Chem. 1939,128, 537.
3. Z. Zhang, B. Xiang, Zhang, D. An,Fenxi Hauxue 1992,20, 652.
4. I. M. Barwick, P. Warwick, N. T. Crosby,Analyst 1993,118, 489.
5. M. E. Ei-Kommos, K. M. Emara,Analyst 1988,113, 133.