Nguyen, Thi Ngoc Bich, Minh Giang Nguyen, and Thi Yen Thanh Nguyen. 2025. “INTEGRATING EDUCATION FOR SUSTAINABLE DEVELOPMENT INTO THE ‘EARTH AND SKY’ THEME IN GRADE 2 NATURAL SCIENCES AND SOCIAL STUDIES: A PROJECT-BASED LEARNING APPROACH”. Ho Chi Minh City University of Education Journal of Science 22 (5):838-49. https://doi.org/10.54607/hcmue.js.22.5.4263(2025).