1. M. G. Megrelishvili, “Compactification and factorization in the category of $$G$$-spaces,” in Categorical Topology and its Relation to Analysis, Algebra and Combinatorics (World Sci. Publ., Singapore, 1989), pp. 220–237.
2. J. de Vries, Topological Transformation Groups 1. A Categorical Approach (Mathematisch Centrum, Amsterdam, 1975).
3. E. V. Mart’yanov, “Characterization of $$\mathbb R$$-factorizable $$G$$-spaces,” Moscow Univ. Math. Bull. 72 (2), 49–54 (2017).
4. E. V. Mart’yanov, “Equiuniform quotient spaces,” Math. Notes 104 (6), 866–885 (2018).
5. J. De Vries, “On the existence of $$G$$-compactifications,” Bull. Acad. Polon. Sci. Sér. Sci. Math. Astronom. Phys. 26 (3), 275–280 (1978).