APA (7th ed.) Citation

Ayer, A. J. (1977). The problem of knowledge (Repr.). Penguin Books.

Chicago Style (17th ed.) Citation

Ayer, Alfred J. The Problem of Knowledge. Repr. Harmondsworth, Middlesex: Penguin Books, 1977.

MLA (9th ed.) Citation

Ayer, Alfred J. The Problem of Knowledge. Repr. Penguin Books, 1977.