Cita APA (7a ed.)

Ayer, A. (1977). The Problem of Knowledge. Penguin Books.

Cita Chicago Style (17a ed.)

Ayer, A.J. The Problem of Knowledge. Estados Unidos: Penguin Books, 1977.

Cita MLA (9a ed.)

Ayer, A.J. The Problem of Knowledge. Penguin Books, 1977.