PetuninY. I., and RublevВ. V. “Minimum-Area Ellipse Containing a Finite Set of Points. II”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 50, no. 8, Aug. 1998, pp. 1098–1105, https://umj.imath.kiev.ua/index.php/umj/article/view/4859.