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.
Atenció: Aquestes cites poden no estar 100% correctes.