APA (7th ed.) Citation

United States. Patent Office. (1921). Index of patents issued from the United States Patent Office. Government Printing Office.

Chicago Style (17th ed.) Citation

United States. Patent Office. Index of Patents Issued from the United States Patent Office. Washington: Government Printing Office, 1921.

MLA (9th ed.) Citation

United States. Patent Office. Index of Patents Issued from the United States Patent Office. Government Printing Office, 1921.