Cita APA (7th ed.)

Birley, A. (1999). Septimius Severus: The African emperor. Routledge.

Cita Chicago (17th ed.)

Birley, Anthony. Septimius Severus: The African Emperor. London ; New York: Routledge, 1999.

Cita MLA (9th ed.)

Birley, Anthony. Septimius Severus: The African Emperor. Routledge, 1999.