Ronald N. Goldman Wenping Wang Using Invariants To Extract Geometric Characteristics Of Conic Sections From Rational Quadratic Parameterizations. 161-187 2004 14 Int. J. Comput. Geometry Appl. 3 http://dx.doi.org/10.1142/S021819590400141X db/journals/ijcga/ijcga14.html#GoldmanW04