APA (7th ed.) Citation

British Standards Institution. (1965). Cast iron butterfly valves for general purposes. British Standards Institution.

Chicago Style (17th ed.) Citation

British Standards Institution. Cast Iron Butterfly Valves for General Purposes. London: British Standards Institution, 1965.

MLA (8th ed.) Citation

British Standards Institution. Cast Iron Butterfly Valves for General Purposes. British Standards Institution, 1965.