Laparoscopy-Assisted Billroth I Gastrectomy for Ectopic Pancreas in the Prepyloric Region oleh Yueh-Tsung Lee, Ho Lin, Jen-Chang Guo, Sheng-Lei Yan, Hsiang-Jen Hou, Yih-Shyong Lai, Yi-Hsiang Liu, Hurng-Sheng Wu, Min-Ho Hwang