APA (7th ed.) Citation

O'Brien, C. C. (1972). States of Ireland ([1st American ed.].). Pantheon Books.

Chicago Style (17th ed.) Citation

O'Brien, Conor Cruise. States of Ireland. [1st American ed.]. New York: Pantheon Books, 1972.

MLA (8th ed.) Citation

O'Brien, Conor Cruise. States of Ireland. [1st American ed.]. Pantheon Books, 1972.