I. Y. . Ivanov and S. G. . Kosaretsky, “Inequality of children’s opportunities in extracurricular education in post-Soviet countries”, Журнал Белорусского государственного университета. Социология, no. 4, pp. 58–68, Dec. 2021, doi: 10.33581/2521-6821-2021-4-58-68.