Takayuki Nagai Seigo Yasutome Nobuki Tokura Convex hull problem with imprecise input and its solution. 31-42 1999 30 Systems and Computers in Japan 3 http://dx.doi.org/10.1002/(SICI)1520-684X(199903)30:3<31::AID-SCJ4>3.0.CO;2-B db/journals/scjapan/scjapan30.html#NagaiYT99