Quan Thị D. INTEGRATING EDUCATION OF SEA AND ISLAND SOVEREIGNTY IN GEOGRAPHY TEACHING GRADE 9 TUYEN QUANG HIGH SCHOOL. SJ TTU [Internet]. 2023Dec.19 [cited 2024May8];8(1). Available from: https://tckh.daihoctantrao.edu.vn/index.php/sjttu/article/view/713