4Wilson J F. Survey of reference ranges and clinical measurements for psychoactive drugs in serum. Ther Drug Monit,2003 ,25(2):243.
5Zucchelli G C, Pilo A, Chiesa M R, et al. Progress report of an external quality assessment scheme for cyclosporine assay. Ther Drug Monit, 1996,18(3 ) : 273.
6Roberts W L, Annesley T M, De B K, Moulton L, Juenke J M,Moyer T P. Performance characteristics of four free phenytoin immunoassays. Ther Drug Monit ,2001 ,23(2) : 148.