APA (7th ed.) Citation

United States. Patent Office. (1938). Official gazette of the United States Patent Office, [title page, contents, etc., to] Vol. 491; June 1938. [s.n.].

Chicago Style (17th ed.) Citation

United States. Patent Office. Official Gazette of the United States Patent Office, [title Page, Contents, Etc., to] Vol. 491; June 1938. [Washington]: [s.n.], 1938.

MLA (9th ed.) Citation

United States. Patent Office. Official Gazette of the United States Patent Office, [title Page, Contents, Etc., to] Vol. 491; June 1938. [s.n.], 1938.