Dirican, A., B. Unal, B. Isik, F. Sumer, C. Kayaalp, and I. Aslan. “Corelation Between Preoperative Serum CEA, CA19-9, and AFP Levels and Clinicopathologic Factors”. Annals of Medical Research, vol. 15, no. 4, May 2021, pp. 0233-7, http://www.annalsmedres.org/index.php/aomr/article/view/3294.