APA (7th ed.) Citation

Brown, G. I. (1953). A simple guide to modern valency theory. Longmans, Green.

Chicago Style (17th ed.) Citation

Brown, G. I. A Simple Guide to Modern Valency Theory. London, New York: Longmans, Green, 1953.

MLA (9th ed.) Citation

Brown, G. I. A Simple Guide to Modern Valency Theory. Longmans, Green, 1953.