APA (7th ed.) Citation

Clean Air Conference (Great Britain) & National Society for Clean Air. (1968). Clean air conference. National Society for Clean Air.

Chicago Style (17th ed.) Citation

Clean Air Conference (Great Britain) and National Society for Clean Air. Clean Air Conference. London: National Society for Clean Air, 1968.

MLA (8th ed.) Citation

Clean Air Conference (Great Britain) and National Society for Clean Air. Clean Air Conference. National Society for Clean Air, 1968.