APA (7th ed.) Citation

O'Hear, A. (1980). Karl Popper. Routledge & K. Paul.

Chicago Style (17th ed.) Citation

O'Hear, Anthony. Karl Popper. London: Routledge & K. Paul, 1980.

MLA (9th ed.) Citation

O'Hear, Anthony. Karl Popper. Routledge & K. Paul, 1980.