http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
TOEFL - iBT bí quyết và thành công
Hướng dẫn và bài tập luyện thi TOEFL
Huỳnh Thị Ái Nguyên, Nguyễn Quang Vịnh