Renaldi, Kaka, et al. “Serum CA 19-9 of Pancreatic Solid Mass Patients in Dr. Cipto Mangunkusumo National Central General Hospital”. The Indonesian Journal of Gastroenterology, Hepatology, and Digestive Endoscopy, vol. 21, no. 3, Dec. 2020, pp. 188-92, doi:10.24871/2132020188-192.