外接円
↑ Megiddo 1983.
↑ Whitworth, William Allen. Trilinear Coordinates and Other Methods of Modern Analytical Geometry of Two Dimensions, Forgotten Books, 2012 (orig. Deighton, Bell, and Co., 1866). http://www.forgottenbooks.com/search?q=Trilinear+coordinates&t=books
↑ Weisstein, Eric W. "barycentric coordinates". mathworld.wolfram.com (英語).
1 2 Johnson, Roger A., Advanced Euclidean Geometry, Dover, 2007 (orig.