Cita APA (7a ed.)

Ayer, A. J. (1956). The problem of Knowledge. Penguin.

Cita Chicago Style (17a ed.)

Ayer, A. J. The Problem of Knowledge. Harmondsworth: Penguin, 1956.

Cita MLA (9a ed.)

Ayer, A. J. The Problem of Knowledge. Penguin, 1956.