Columbia subject headings:
Rome--History--Lucius Septimius Severus, 193-211.
Severus, Lucius Septimius, Emperor of Rome, 146-211.
Harvard subject headings:
Rome--History--Lucius Septimius Severus, 193-211.
Severus, Lucius Septimius, Emperor of Rome, 146-211.
Princeton subject headings: