Cita APA (7a ed.)

Buchan, J. (1993). The thirty nine steps. Penguin Books.

Cita Chicago Style (17a ed.)

Buchan, John. The Thirty Nine Steps. London: Penguin Books, 1993.

Cita MLA (9a ed.)

Buchan, John. The Thirty Nine Steps. Penguin Books, 1993.