1. Council of Europe. (2001). Common European Framework of Reference for languages: Learning, teaching, assessment. Cambridge University Press. https://rm.coe.int/1680459f97
2. Council of Europe. (2020). Common European Framework of Reference for languages: Learning, teaching, assessment—Companion volume with new descriptors. Council of Europe Publishing. https://rm.coe.int/common-european-framework-of-reference-for-languages-learning-teaching/16809ea0d4
3. Second language acquisition: Theoretical and experimental issues in contemporary research
4. The role of L1 explicit metalinguistic knowledge in L3 oral production at the initial state
5. Kabinet Ministriv Ukrayiny. (2021a, April 14). Postanova: Pro zatverdzhennya poryadku provedennya ispytiv na riven’ volodinnya derzhavnoyu movoyu [Decree on the procedure for conducting the exams of the level of mastery of the official language]. https://zakon.rada.gov.ua/laws/show/409-2021-%D0%BF#Text