Ramos Ramírez MC, Toapaxi G, Tinajero F. Marcador Tumoral Ca 19,9 pre y post quimioterapia, como factor pronóstico Cáncer Gástrico: Tumor marker CA 19.9 pre and post chemotherapy, as a prognostic factor, Gastric Cancer. lauinvestiga [Internet]. 2018 Jun. 30 [cited 2025 Apr. 4];5(1):32-40. Available from: http://revistasojs.utn.edu.ec/index.php/lauinvestiga/article/view/373