• Richard Alston - "Soldier and Society in Roman Egypt: A social history", Routledge Press 1995.
• Emil Ritterling - "Legio" article published in Realencyclopädie of Klassischen Altertumswissenschaft in 1925 Lưu trữ 2012-02-24 tại Wayback Machine
• H. A. Sanders - JSTOR article written 1941)
• John Paul Adams - (California State University, Northridge)
• Adrian Goldsworthy - "The Complete Roman Army", Thames & Hudson 2003.
• Jona Lendering - Livius.org
• Peter Connolly - "Greece and Rome at War", Greenhill Books 1981, 1998.
• Phil Barker - "The Armies and Enemies of Imperial Rome", Wargames Research Group Publications 1981.
• Bishop & Coulston - "Roman Military Equipment", Oxbow Books 1993.
• De Imperatoribus Romanis (On the Roman Emperors)

Osprey books:

• Simkins / Embelton - The Roman Army from Caesar to Trajan (Men at Arms #46)
• Cowan / McBride - Roman Legionary: 58 BC - AD 69 (Warrior #71)
• Sumner - Roman Military Clothing 1,2,3 (Men at Arms #374, 390, 425)
• Campbell / Hook - Siege Warfare in the Roman World (Elite #126)
• Cowan / Hook - Roman Battle Tactics: 109 BC - AD 313 (Elite #155)
• Gilliver / Goldsworthy / Whitby - Rome At War: Caesar and his Legacy (Essential Histories)