APA (7th ed.) Citation

(1924). U.S. Government master specification for asphalt for unsurfaced built-up roofing. U.S. Government Printing Office.

Chicago Style (17th ed.) Citation

U.S. Government Master Specification for Asphalt for Unsurfaced Built-up Roofing. [Washington?]: U.S. Government Printing Office, 1924.

MLA (9th ed.) Citation

U.S. Government Master Specification for Asphalt for Unsurfaced Built-up Roofing. U.S. Government Printing Office, 1924.