TATAR, Gonca, et al. “PORTAL VEIN THROMBOSIS AND CAVERNOUS TRANSFORMATION IN TWO PATIENTS WITH PEPTIC ULCER”. Turkish Journal of Gastroenterology, vol. 3, no. 4, Jan. 1992, pp. 768-70, https://www.turkjgastroenterol.org/index.php/tjg/article/view/173.