APA (7th ed.) Citation

Ayer, A. J. (1976). The problem of knowledge. Penguin Books.

Chicago Style (17th ed.) Citation

Ayer, A. J. The Problem of Knowledge. Middlesex, Eng.: Penguin Books, 1976.

MLA (9th ed.) Citation

Ayer, A. J. The Problem of Knowledge. Penguin Books, 1976.

Warning: These citations may not always be 100% accurate.