TKACHENKO, Olena. “Research of the Emotional Component of First-graders’ Adaptation to School As an Indicator of the Effectiveness of the Implementation of the Principles of New Ukrainian School in the Educational Process”. EUROPEAN HUMANITIES STUDIES: State and Society, vol. 19, no. 3(I), Sept. 2019, pp. 52-63, doi:10.38014/ehs-ss.2019.3-I.05.