Dasgupta A, Dennen DA, Dean R, McLawhon RW, Prediction of free phenytoin levels based on [total phenytoin]/[albumin] ratios. Potential errors with hypoalbuminemia, Am J Clin Pathol, 1991 Feb;95(2):253-6

Martin E, Tozer TN, Sheiner LB, Riegelman S, The clinical pharmacokinetics of phenytoin, J Pharmacokinet Biopharm, 1977 Dec;5(6):579-96