APA (7th ed.) Citation

British Standards Institution. (1969). Universal decimal classification (4th international ed.). British Standards Institution.

Chicago Style (17th ed.) Citation

British Standards Institution. Universal Decimal Classification. 4th international ed. London: British Standards Institution, 1969.

MLA (8th ed.) Citation

British Standards Institution. Universal Decimal Classification. 4th international ed. British Standards Institution, 1969.

Warning: These citations may not always be 100% accurate.