Cita APA (7th ed.)

Ayer, A. J. (1956). Problem of knowledge. Middlesex Penguin.

Cita Chicago (17th ed.)

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

Cita MLA (9th ed.)

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