APA (7th ed.) Citation

Ayer, A. J. (1973). The central questions of philosophy. Penguin Books.

Chicago Style (17th ed.) Citation

Ayer, A. J. The Central Questions of Philosophy. [Middlesex; New York]: Penguin Books, 1973.

MLA (9th ed.) Citation

Ayer, A. J. The Central Questions of Philosophy. Penguin Books, 1973.