http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
David R. Anderson, Dennis J. Sweeney, Thomas A. Williams
Kinh tế,Commercial statistics,Economics,Thống kê thương mại
Phương pháp thống kê,Methodology,Statistical methods,Phương pháp học