“The relationship of preoperative and postoperative serum CEA and CA 19-9 levels with tumor localization, stage and overall survival in patients with colorectal cancer ”, Ann Med Res , vol. 28, no. 4, pp. 0726–0732, May 2021, Accessed: Apr. 04, 2025. [Online]. Available: http://annalsmedres.org/index.php/aomr/article/view/465