I. Ben Yaacov, J. Melleray, and T. Tsankov, Metrizable universal minimal flows of Polish groups have a comeagre orbit.Geometric and Functional Analysis, vol. 27 (2017), no. 1, pp. 67-77. - J. Melleray, L. Nguyen Van Thé, and T. Tsankov, Polish groups with metrizable universal minimal flows. International Mathematics Research Notices, vol. 2016, no. 5, pp. 1285-1307.