THE EFFECTIVENESS AND IMPACT OF THE “LESSON STUDY” APPROACH ON THE DEVELOPMENT OF TEACHERS’ PROFESSIONAL COMPETENCIES AND SKILLS. Educ-21st-Century [Internet]. 2025 Apr. 25 [cited 2026 Jan. 22];6(2):32-4. Available from: https://journals.ysu.am/index.php/Educ-21st-Century/article/view/12501