Defining surgical difficulty according to the perceived complexity of liver resection: Validation of a complexity classification system for prospective liver resection in hepatocellular carcinoma. (April 2016) - Muangkaew, P.; Cho, J.Y.; Han, H.S.; Yoon, Y.S.; Choi, Y.R.; Jang, J.Y.; Choi, H.L.; Jang, J.S.; Kwon, S.U.