http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Bài giảng giới thiệu phương pháp hai hình chiếu thẳng gốc như điểm - đường thẳng - mặt phẳng, các phép biến đổi hình chiếu...