WilsonJFTsanaclisLMPerrettJEWilliamsJWicksJFCRichensA. Performance of techniques for measurement of therapeutic drugs in serum. A comparison based on external quality assessment data. Ther Drug Monit1992: 14: 98–106.
2.
LeloAMinersJORobsonRBirkettDJ. Assessment of caffeine exposure: Caffeine content of beverages, caffeine intake, and plasma concentrations of methylxanthines. Clin Pharmacol Ther1986; 39: 54–9.