Cita APA (7a ed.)

Buchan, J. (1971). Cromwell (1st Sphere Books edition.). Sphere Books.

Cita Chicago Style (17a ed.)

Buchan, John. Cromwell. 1st Sphere Books edition. London: Sphere Books, 1971.

Cita MLA (9a ed.)

Buchan, John. Cromwell. 1st Sphere Books edition. Sphere Books, 1971.