Carvalho, Ramiro, C. Leichsenring, J. Félix, Fernando R. Gomes, Rita Theias, V. Geraldes, L. Cuña, F. Branquinho, and Maria do Carmo Perloiro. 2010. “Association Between Pernicious Anemia and Gastric Carcinoid Tumor: A Report of a Clinical Case”. Internal Medicine 17 (1). Lisboa, Portugal:35-40. https://revista.spmi.pt/index.php/rpmi/article/view/1274.