1. Pavlenko T.A., Kostenetsky M.I., Kutsak A.V., Sevalnev A.I., Aksenov N.V., Frizyuk M.A. Levels of exposure of preschool children due to indoor radon. Gigiena i sanitariya = Hygiene and sanitation, 2015, No 4, pp. 18–21(in Russian).
2. Stamat I.P., Kormanovskaya T.A., Svetovidov A.V., Rakitin I.A., Gorsky G.A. Levels of children exposure from natural ionizing sources at child educational institutions in the territory of some Russian Federation subject territories. Radiatsionnaya Gygiena = Radiation Hygiene, 2011, Vol. 4, No 1, pp. 14–19 (in Russian).
3. Zunic Z., Carpentieri C., Stojanovska Z. [et al.] Some results of a radon survey in 207 Serbian schools. Rom. J. Phys., 2013, No 58, pp. 320–327.
4. Ivanova K., Stojanovska Z., Tsenova M. [et al.] Measurement of indoor radon concentration in kindergartens in Sofia, Bulgaria. Radiat. Prot. Dosimetry, 2015, No 162, pp. 163–166.
5. Bem H., Bem E.M., Krawczyk J. [et al.] Radon concentrations in kindergartens and schools in two cities: Kalisz and Ostrow Wielkopolski in Poland. Journal of Radioanalytical and Nuclear Chemistry, 2013, No 295, pp. 2229–2232.