My greatest gratitude goes to my supervisor -Professor Anikó Zsolnai, whose commitment, professional guidance, generosity of spirit, and patience helped me to accomplish this process of becoming a researcher and a better teacher.I sincerely thank my advisers Professor Nguyễn Lưu Lan Anh and Professor Garai Imre whose invaluable support and professional advice helped me through this journey. I am also very grateful to all professors, senior students, and administrative personnel at the Faculty of Education and Psychology (PPK), Eötvös Loránd University (ELTE).I especially thank the reviewers of my pre-defence and public defence, the members, the chair and the secretary of the defence committee for the time and effort dedicated to my dissertation and your invaluable suggestions.To Hong Duc University, Vietnam, for nominating me for this study and, in particular, to Tempus Foundation, whose generosity in availing me funds performed the magic of my study in PPK, ELTE. I am always grateful.To my research participants who were primary school teachers in different areas of Thanh Hoa province, Vietnam, without your generosity in availing information from your experiences, availability for the study, and wisdom, the completion of this study would have been impossible. Your love for our nation's young children and your passion for our most prestigious profession-Teacher have inspired and motivated me to work harder and learn faster to contribute better to our nation's education. To the principals of the participating schools who permitted me to use your schools in this study, I am sincerely thankful.To my friends Huỳnh Ngọc Thu Hương, Adrian Estrela Pereira, and Daria Borodina who sacrificed your time when I needed you at different times of the study, I sincerely thank you very much.My deepest and forever-lasting gratitude to my family who has brought me up as a healthy and happy person, who enjoys her life and loves studying, and who was not scared to start a challenging doctoral journey. My family's wellness, love, and support are what I am grounded on.