http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Guide to U.S. Government serials & periodicals
Guide to United States Government serials and periodicals
"Basic volumes published in March and a supplement, which updates the information through June 30 of each year, issued in September."
"Pilot ed." issued 1959 under title: U.S. Government serials and periodicals (Z1223.Z7A57)