Ganikhodzhaev, N. N., et al. “Nonergodic Quadratic Operators for a Two-Sex Population”. Ukrains’kyi Matematychnyi Zhurnal, vol. 65, no. 8, Aug. 2013, pp. 1152–1160, https://umj.imath.kiev.ua/index.php/umj/article/view/2498.