http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Lựa chọn phương thức đầu tư cơ giới hóa nông nghiệp: Tài liệu của FAO về dịch vụ nông nghiệp
agricultural machinery,farm mechanization