http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Preliminary report. Industry series. Roofing and sheet metal work special trade contractors (industry 1761)
Census of construction industries (1982)
Industry series, roofing and sheet metal work special trade contractors (industry 1761)
Roofing and sheet metal work special trade contractors (industry 1761)