Lai, Wen-Jia, and Yi-Kai Xu. “A Rare Case of a Heavily Calcified Gastrointestinal Stromal Tumors With an Intraluminal Growth Pattern”. Turkish Journal of Gastroenterology, vol. 26, no. 3, Jan. 2015, pp. 277-8, doi:10.5152/tjg.2015.7887.