http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Bài tập địa lí 9 được biên soạn nhằm nâng cao chất lượng và hiệu quả của quá trình dạy-học địa lí 9 ở trường THCS
Dạy và học (Trung học),Study and teaching (Secondary)