APA (7th ed.) Citation

World Intellectual Property Organization. (1994). International patent classification (6th ed.). World Intellectual Property Organization.

Chicago Style (17th ed.) Citation

World Intellectual Property Organization. International Patent Classification. 6th ed. [Geneva, Switzerland]: World Intellectual Property Organization, 1994.

MLA (9th ed.) Citation

World Intellectual Property Organization. International Patent Classification. 6th ed. World Intellectual Property Organization, 1994.