Keson Trakunram และผู้แต่งคนอื่นๆ. (2018) Solid-phase extraction for determination of caffeine and itsdimethylxanthine metabolites in rat urine using high performanceliquid chromatography and its application. <i>Songklanakarin Journal of Science and Technology</i>, <i>40</i>(4), 759.Keson Trakunram และผู้แต่งคนอื่นๆ. "Solid-phase extraction for determination of caffeine and itsdimethylxanthine metabolites in rat urine using high performanceliquid chromatography and its application". Songklanakarin Journal of Science and Technology 40 (2018):759.Keson Trakunram และผู้แต่งคนอื่นๆ. Solid-phase extraction for determination of caffeine and itsdimethylxanthine metabolites in rat urine using high performanceliquid chromatography and its application. Research and Development Office, Prince of Songkla University:ม.ป.ท. 2018.