APA (7th ed.) Citation

Brown, G. I. (1954). A simple guide to modern valency theory. Longmans.

Chicago Style (17th ed.) Citation

Brown, George Ingham. A Simple Guide to Modern Valency Theory. London: Longmans, 1954.

MLA (9th ed.) Citation

Brown, George Ingham. A Simple Guide to Modern Valency Theory. Longmans, 1954.