Rajabto, Wulyo, et al. “Iron Deficiency Anemia As The Only Manifestation of Colon Cancer in Male Patient: A Case Report”. The Indonesian Journal of Gastroenterology, Hepatology, and Digestive Endoscopy, vol. 21, no. 3, Dec. 2020, pp. 241-3, doi:10.24871/2132020241-243.