United States. Patent Office. (1938). Official gazette of the United States Patent Office, June 21, 1938. [s.n.].
Chicago Style (17th ed.) CitationUnited States. Patent Office. Official Gazette of the United States Patent Office, June 21, 1938. [Washington]: [s.n.], 1938.
MLA (9th ed.) CitationUnited States. Patent Office. Official Gazette of the United States Patent Office, June 21, 1938. [s.n.], 1938.
Warning: These citations may not always be 100% accurate.