Ardianto, Taufiq, Warsinggih Warsinggih, and Arifin Seweng. 2019. “Correlation Between Histopathological Grading and Appearance of Obstruction With Level of Carsino-Embryonic Antigen (CEA) in Colorectal Carcinoma”. International Journal of Sciences: Basic and Applied Research (IJSBAR) 45 (2): 31-38. https://gssrr.org/JournalOfBasicAndApplied/article/view/9932.