“Oesophagus Esofago (C15.9) - Prognostic Significance of Preoperative Serum CA 72-4 and CA 242 in Patients With Esophageal Squamous Cell Carcinoma”. 2014. European Journal of Oncology and Environmental Health 18 (3): 139-46. https://mattioli1885journals.com/index.php/EJOEH/article/view/3446.