APA (7th ed.) Citation

Cowan, R., & Ó'Brógáin, S. (2014). Roman guardsman, 62 BC-AD 324 (1st published.). Osprey.

Chicago Style (17th ed.) Citation

Cowan, Ross, and Seán Ó'Brógáin. Roman Guardsman, 62 BC-AD 324. 1st published. Oxford: Osprey, 2014.

MLA (9th ed.) Citation

Cowan, Ross, and Seán Ó'Brógáin. Roman Guardsman, 62 BC-AD 324. 1st published. Osprey, 2014.