1. K.J. Himmelstein, T.F. Patton, R.J. Belt, S. Taylor, A.J. Refta and L.A. Sernson, Clin. Pharmacol. Ther., 29 (1981) 658.
2. S.Caroli, F. Petrucci, F. la Torre, A. Alimonli, A. Cifani, C. Dominici and M.A. Castello, Trace Elem. Anal. Chem. Med. Biol. Proc. Int. Work, 5 (1988) 310.
3. Y. Chen and J. Guo, Guangpoxue Yu Guangpu Fenxi, 11 (1991) 48.
4. A. El-Yazigi and I. Al-Saleh, Ther. Drug. Monit., 8 (1986) 318.
5. K. Winnefeld, E. Tennigkeit, H. Dawszynski and K. Ruffert, Jena Rev., 28 (1983) 139.