http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Gồm 4 chương: Phép toán đại số và nửa nhóm; Nhóm; Vành và trường; Một số loại vành đặc biệt. Cuối mỗi chương có một số bài tập chọn lọc.