Tran Thi D. IMPROVING THE ECONOMIC EFFICIENCY OF GRAPEFRUIT FARMS IN PHUC NINH COMMUNE - YEN SON DISTRICT - TUYEN QUANG PROVINCE. SJ TTU [Internet]. 2022Apr.12 [cited 2024May18];7(24). Available from: http://tckh.daihoctantrao.edu.vn/index.php/sjttu/article/view/684