What Makes a Top-Performing Precision Medicine Search Engine? - Huang, Jimmy; Chang, Yi; Cheng, Xueqi; Kamps, Jaap; Murdock, Vanessa; Wen, Ji-Rong; Liu, Yiqun; Faessler, Erik; Oleynik, Michel; Hahn, Udo (Proceedings of the 43rd International ACM SIGIR Conference on Research and Development in Information Retrieval, 2020)