http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Tuyển chọn các bài toán lượng giác; T1
Đẳng thức lượng giác, bất đẳng thức lượng giác, phương trình và bất phương trình lượng giác chứa tham số