United States. Patent Office. (1917). Classification of patents. U.S. GPO.
Chicago Style (17th ed.) CitationUnited States. Patent Office. Classification of Patents. Washington: U.S. GPO, 1917.
MLA (9th ed.) CitationUnited States. Patent Office. Classification of Patents. U.S. GPO, 1917.
Warning: These citations may not always be 100% accurate.