APA (7th ed.) Citation

Eysenck, H. J. (1966). Check your own I.Q (First published.). Penguin Books.

Chicago Style (17th ed.) Citation

Eysenck, H. J. Check Your Own I.Q. First published. Harmondsworth: Penguin Books, 1966.

MLA (9th ed.) Citation

Eysenck, H. J. Check Your Own I.Q. First published. Penguin Books, 1966.