Jelaskan Rujukan dari Auto Union dalam bahasa melayu

Bruintjes, Jeroen. "Auto Union Type E—The Stillborn 1.5-litre car: Why it (Almost) did Exist"

Snellman, Leif. "The Early Auto Unions, From P-Wagen to A-type"

Wise, David Burgess. "Rumpler: One Aeroplane which Never Flew", in Northey, Tom, ed. World of Automobiles (London: Orbis, 1974), Vol. 17, p. 1964.<